4u is a cutting edge Italian seating series designed by S.I. Design. The flowing sleek lines of this chair add to the ambiance of sophistication in any environment while also providing incredible ergonomics, comfort, and functionality. A range of back offerings in mesh, upholstered, or the newest, welded fabric “groove”, which is a sleek and comfortable hybrid of both mesh and fabric. Both white and black frames are available with matching arms and bases. There are extensive arm choices including custom 4u 6-way adjustable armrest—angle, width and height adjustments—and multiple body balance and synchro options enabling you to customize to your exact needs. 4u offers two seat shape options: the euro slim line sit and the enhanced comfort sit. Also available as task stools.
There’s no doubt about it. This chair is 4u.
user guide: view the guide (pdf)→
Lorenzo Negrello was born in Pádova in 1953. He Graduatd in Architecture in Venice in 1977. From 1978 to 1988, he was a teacher of design at the Institute of Art in Pádova and at the Art Lycée in Venice. Between 1980 and 1996, designer Lorenzo Negrello worked in partnership with architect Paolo Scagnellato, with two projects being nominated for the “Compasso d’Oro” Industrial Design award.
In 1996 Lorenzo founded S.I. Design with designers Mirco Pegoraro and Mauro Naletto. S.I. specializes in furniture design, particularly for offices and communal spaces. Today, their team of eight focuses on design and technical assistance in product development utilizing advanced modeling programs.
studio: Pádova, Italy.
seats | Medium SL (780) | Medium EC (781) | Large SL (782) | Large EC (783) |
A | 37.3″ – 42.1″ | 39.7″ – 41.9″ | 37.3″ – 42.1″ | 36.9″ – 41.7″ |
B | 16.6″ – 21.4″ | 17.6″ – 19.7″ | 15.6″ – 20.4″ | 17.8″ – 22.6″ |
C | 19.5″ | 21.0″ | 20.5″ | 22.2″ |
D | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ |
E | 22.5″ | 21.7″ | 22.5″ | 21.9″ |
F | 28.2″ | 27.4″ | 28.2″ | 27.9″ |
G | 16.3″ | 15.1″ | 16.3″ | 18.3″ |
seats | Medium SL (780) | Medium EC (782) | Large SL (781) | Large EC (783) |
A | 38.2″ – 43.0″ | 40.6″ – 45.4″ | 38.2″ – 43.0″ | 37.8″ – 42.6″ |
B | 17.1″ – 21.9″ | 18.1″ – 22.9″ | 16.1″ – 20.9″ | 18.3″ – 23.1″ |
C | 19.5″ | 21.0″ | 20.5″ | 22.2″ |
D | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ |
E | 21.5″ | 20.7″ | 21.5″ | 20.9″ |
F | 28.2″ | 27.4″ | 28.2″ | 27.9″ |
G | 15.1″ – 17.1″ | 13.9″ – 15.9″ | 15.1″ – 17.1″ | 17.1″ – 19.1″ |
seats | Medium SL (780) | Medium EC (782) | Large SL (781) | Large EC (783) |
A | 37.6″ – 42.4″ | 40.0″ – 44.8″ | 37.6″ – 42.4″ | 37.2″ – 42.0″ |
B | 16.7″ – 21.5″ | 17.7″ – 22.5″ | 15.7″ – 20.5″ | 17.9″ – 22.7″ |
C | 19.5″ | 21.0″ | 20.5″ | 22.2″ |
D | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ |
E | 22.2″ | 21.4″ | 22.2″ | 21.6″ |
F | 28.2″ | 27.4″ | 28.2″ | 27.9″ |
G | 17.1″ | 15.9″ | 17.1″ | 19.1″ |
seats | Medium SL (780) | Medium EC (781) | Large SL (782) | Large EC (783) |
A | 37.6″ – 42.4″ | 40.0″ – 44.8″ | 37.6″ – 42.4″ | 37.2″ – 42.0″ |
B | 17.2″ – 22.0″ | 18.2″ – 23.0″ | 16.2″ – 21.0″ | 18.4″ – 23.2″ |
C | 19.5″ | 21.0″ | 20.5″ | 22.2″ |
D | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ |
E | 21.7″ | 20.9″ | 21.7″ | 21.6″ |
F | 28.2″ | 27.4″ | 28.2″ | 27.9″ |
G | 16.5″ – 18.5″ | 15.3″ – 17.3″ | 16.5″ – 18.5″ | 18.5″ – 20.5″ |
seats | Medium SL (785) | Medium EC (787) | Large SL (786) | Large EC (788) |
A | 37.2″ – 42.0″ | 37.1″ – 41.9″ | 37.2″ – 42.0″ | 36.9″ – 41.7″ |
B | 16.2″ – 21.0″ | 17.5″ – 21.3″ | 16.1″ – 20.9″ | 17.8″ – 22.6″ |
C | 19.5″ | 21.0″ | 20.5″ | 22.2″ |
D | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ |
E | 22.9″ | 22.0″ | 22.5″ | 21.9″ |
F | 24.8″ | 27.0″ | 26.2″ | 27.9″ |
G | 16.1″ | 18.6″ | 16.1″ | 18.3″ |
seats | Medium SL (785) | Medium EC (787) | Large SL (786) | Large EC (788) |
A | 38.1″ – 42.9″ | 38.0″ – 42.8″ | 38.1″ – 42.9″ | 37.8″ – 42.6″ |
B | 16.7″ – 21.5″ | 18.0″ – 22.8″ | 16.6″ – 21.4″ | 18.3″ – 23.1″ |
C | 19.5″ | 21.0″ | 20.5″ | 22.2″ |
D | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ |
E | 22.9″ | 21.0″ | 21.5″ | 20.9″ |
F | 24.8″ | 27.0″ | 26.2″ | 27.9″ |
G | 14.9″ – 16.9″ | 17.4″ – 19.4″ | 14.9″ – 16.9″ | 17.1″ – 19.1″ |
seats | Medium SL (785) | Medium EC (787) | Large SL (786) | Large EC (788) |
A | 37.5″ – 42.3″ | 37.4″ – 42.2″ | 37.5″ – 42.3″ | 37.2″ – 42.0″ |
B | 16.3″ – 21.1″ | 17.6″ – 22.4″ | 16.2″ – 21.0″ | 17.9″ – 22.7″ |
C | 19.5″ | 21.0″ | 20.5″ | 22.2″ |
D | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ |
E | 22.6″ | 21.7″ | 22.2″ | 21.6″ |
F | 24.8″ | 27.0″ | 26.2″ | 27.9″ |
G | 16.9″ | 19.4″ | 16.9″ | 19.1″ |
seats | Medium SL (785) | Medium EC (787) | Large SL (786) | Large EC (788) |
A | 37.5″ – 42.3″ | 37.4″ – 42.2″ | 37.5″ – 42.3″ | 37.2″ – 42.0″ |
B | 16.8″ – 21.6″ | 18.1″ – 22.9″ | 16.7″ – 21.5″ | 18.4″ – 23.2″ |
C | 19.5″ | 21.0″ | 20.5″ | 22.2″ |
D | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ |
E | 22.1″ | 21.2″ | 21.7″ | 21.6″ |
F | 24.8″ | 27.0″ | 26.2″ | 27.9″ |
G | 16.3″ – 18.3″ | 18.8″ – 20.8″ | 16.3″ – 18.3″ | 18.5″ – 20.5″ |
seats | Medium SL (770) | Medium EC (772) | Large SL (771) | Large EC (773) |
A | 37.2″ – 42.0″ | 37.2″ – 42.0″ | 38.1″ – 42.9″ | 37.2″ – 42.0″ |
B | 16.2″ – 21.0″ | 17.0″ – 21.8″ | 16.4″ – 21.2″ | 18.2″ – 22.6″ |
C | 19.5″ | 21.0″ | 20.5″ | 22.2″ |
D | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ |
E | 23.0″ | 22.6″ | 23.0″ | 22.0″ |
F | 24.8″ | 26.0″ | 25.1″ | 27.9″ |
G | 16.2″ | 16.1″ | 16.2″ | 17.4″ |
seats | Medium SL (770) | Medium EC (772) | Large SL (771) | Large EC (773) |
A | 38.1″ – 42.9″ | 38.1″ – 42.9″ | 39.0″ – 43.8″ | 38.1″ – 42.9″ |
B | 16.7″ – 21.5″ | 17.5″ – 22.3″ | 16.9″ – 21.7″ | 18.7″ – 23.5″ |
C | 19.5″ | 21.0″ | 20.5″ | 22.2″ |
D | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ |
E | 23.0″ | 21.6″ | 22.0″ | 21.0″ |
F | 24.8″ | 26.0″ | 25.1″ | 27.9″ |
G | 15.0″ – 17.0″ | 14.9″ – 16.9″ | 15.0″ – 17.0″ | 16.2″ – 18.2″ |
seats | Medium SL (770) | Medium EC (772) | Large SL (771) | Large EC (773) |
A | 37.5″ – 42.3″ | 37.5″ – 42.3″ | 38.4″ – 43.2″ | 37.5″ – 42.3″ |
B | 16.3″ – 21.1″ | 17.1″ – 21.9″ | 16.5″ – 21.3″ | 18.3″ – 23.1″ |
C | 19.5″ | 21.0″ | 20.5″ | 22.2″ |
D | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ |
E | 22.7″ | 22.3″ | 22.7″ | 21.7″ |
F | 24.8″ | 26.0″ | 25.1″ | 27.9″ |
G | 17.0″ | 16.9″ | 17.0″ | 18.2″ |
seats | Medium SL (770) | Medium EC (772) | Large SL (771) | Large EC (773) |
A | 37.5″ – 42.3″ | 37.5″ – 42.3″ | 38.4″ – 43.2″ | 37.5″ – 42.3″ |
B | 16.8″ – 21.6″ | 17.1″ – 21.9″ | 17.0″ – 21.8″ | 18.8″ – 23.6″ |
C | 19.5″ | 21.0″ | 20.5″ | 22.2″ |
D | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ | 18.2″ – 19.0″ |
E | 22.2″ | 21.8″ | 22.2″ | 21.2″ |
F | 24.8″ | 26.0″ | 25.1″ | 27.9″ |
G | 16.4″ – 18.4″ | 16.3″ – 18.3″ | 16.4″ – 18.4″ | 17.6″ – 19.6″ |
controls | 74C | 67C |
C | 19.5″ (74C) 19.5″ (74C-12SS) |
19.5″ (67C) 19.5″ (67C-SS) |
G | 17.1″ (74C) 16.5″ – 19.2″ (74C-12SS) |
16.3″ (67C) 15.1″ – 18.3″ (67C-SS) |
H | 19.4″ (74C) 19.4″ (74C-12SS) |
19.4″ (67C) 19.4″ (67C-SS) |
Additions to starting controls:
controls | 74C | 67C |
C | 21.0″ (74C) 21.0″ (74C-12SS) |
21.0″ (67C) 21.0″ (67C-SS) |
G | 15.9″ (74C) 15.3″ – 17.3″ (74C-12SS) |
15.1″ (67C) 13.9″ – 15.9″ (67C-SS) |
H | 21.0″ (74C) 21.0″ (74C-12SS) |
21.0″ (67C) 21.0″ (67C-SS) |
Additions to starting controls:
controls | 74C | 67C |
C | 20.5″ (74C) 20.5″ (74C-12SS) |
20.5″ (67C) 20.5″ (67C-SS) |
G | 17.1″ (74C) 16.5″ – 18.5″ (74C-12SS) |
16.3″ (67C) 15.1″ – 17.1″ (67C-SS) |
H | 20.0″ (74C) 20.0″ (74C-12SS) |
20.0″ (67C) 20.0″ (67C-SS) |
Additions to starting controls:
controls | 74C | 67C |
C | 22.2″ (74C) 22.2″ (74C-12SS) |
22.2″ (67C) 22.2″ (67C-SS) |
G | 18.3″ (74C) 17.7″ – 19.1″ (74C-12SS) |
19.1″ (67C) 18.5″ – 20.5″ (67C-SS) |
H | 20.0″ (74C) 20.0″ (74C-12SS) |
20.0″ (67C) 20.0″ (67C-SS) |
Additions to starting controls:
controls | 74C | 67C |
C | 19.5″ (74C) 19.5″ (74C-12SS) |
19.5″ (67C) 19.5″ (67C-SS) |
G | 16.9″ (74C) 16.3″ – 18.3″ (74C-12SS) |
16.1″ (67C) 14.9″ – 16.9″ (67C-SS) |
H | 19.4″ (74C) 19.4″ (74C-12SS) |
19.4″ (67C) 19.4″ (67C-SS) |
Additions to starting controls:
controls | 74C | 67C |
C | 21.0″ (74C) 21.0″ (74C-12SS) |
21.0″ (67C) 21.0″ (67C-SS) |
G | 15.9″ (74C) 15.3″ – 17.3″ (74C-12SS) |
15.1″ (67C) 13.9″ – 15.9″ (67C-SS) |
H | 21.5″ (74C) 21.5″ (74C-12SS) |
21.5″ (67C) 21.5″ (67C-SS) |
Additions to starting controls:
controls | 74C | 67C |
C | 20.5″ (74C) 20.5″ (74C-12SS) |
20.5″ (67C) 20.5″ (67C-SS) |
G | 16.9″ (74C) 16.3″ – 18.3″ (74C-12SS) |
16.1″ (67C) 14.9″ – 16.9″ (67C-SS) |
H | 20.0″ (74C) 20.0″ (74C-12SS) |
20.0″ (67C) 20.0″ (67C-SS) |
Additions to starting controls:
controls | 74C | 67C |
C | 22.2″ (74C) 22.2″ (74C-12SS) |
22.2″ (67C) 22.2″ (67C-SS) |
G | 19.1″ (74C) 18.5″ – 20.5″ (74C-12SS) |
18.3″ (67C) 17.1″ – 19.1″ (67C-SS) |
H | 20.0″ (74C) 20.0″ (74C-12SS) |
20.0″ (67C) 20.0″ (67C-SS) |
Additions to starting controls:
controls | 74C | 67C |
C | 19.5″ (74C) 19.5″ (74C-12SS) |
19.5″ (67C) 19.5″ (67C-SS) |
G | 17.0″ (74C) 16.4″ – 18.4″ (74C-12SS) |
16.2″ (67C) 15.0″ – 17.0″ (67C-SS) |
H | 19.4″ (74C) 19.4″ (74C-12SS) |
19.4″ (67C) 19.4″ (67C-SS) |
Additions to starting controls:
controls | 74C | 67C |
C | 21.0″ (74C) 21.0″ (74C-12SS) |
21.0″ (67C) 21.0″ (67C-SS) |
G | 16.9″ (74C) 16.3″ – 18.3″ (74C-12SS) |
16.1″ (67C) 14.9″ – 16.9″ (67C-SS) |
H | 21.5″ (74C) 21.5″ (74C-12SS) |
21.5″ (67C) 21.5″ (67C-SS) |
Additions to starting controls:
controls | 74C | 67C |
C | 20.5″ (74C) 20.5″ (74C-12SS) |
20.5″ (67C) 20.5″ (67C-SS) |
G | 17.0″ (74C) 16.4″ – 18.4″ (74C-12SS) |
16.2″ (67C) 15.0″ – 17.0″ (67C-SS) |
H | 20.0″ (74C) 20.0″ (74C-12SS) |
20.0″ (67C) 20.0″ (67C-SS) |
Additions to starting controls:
controls | 74C | 67C |
C | 22.2″ (74C) 22.2″ (74C-12SS) |
22.2″ (67C) 22.2″ (67C-SS) |
G | 18.2″ (74C) 17.6″ – 19.6″ (74C-12SS) |
17.4″ (67C) 16.2″ – 18.2″ (67C-SS) |
H | 20.0″ (74C) 20.0″ (74C-12SS) |
20.0″ (67C) 20.0″ (67C-SS) |
Additions to starting controls:
seats | slim line | slim line large | extra comfort | extra comfort large |
J | 7.9″ | 7.9″ | 7.9″ | 7.9″ |
K | 5.2″ – 7.6″ | 5.2″ – 7.6″ | 5.2″ – 7.6″ | 5.2″ – 7.6″ |
L | 25.5″ 25.5″ – 29.5″ (19AB) |
26.3″ 26.3″ – 30.0″ (19AB) |
25.5″ 25.5″ – 29.5″ (19AB) |
26.3″ 26.3″ – 30.0″ (19AB) |
M | 19.9″ 19.9″ – 23.9″ (19AB) |
20.7″ 20.7″ – 24.7″ (19AB) |
19.9″ 19.9″ – 23.9″ (19AB) |
20.7″ 20.7″ – 24.7″ (19AB) |
seats | slim line | slim line large | extra comfort | extra comfort large |
J | 7.9″ | 7.9″ | 7.9″ | 7.9″ |
K | 5.5″ – 9.4″ | 5.5″ – 9.4″ | 5.5″ – 9.4″ | 5.5″ – 9.4″ |
L | 27.6″ 27.6″ – 31.6″ (19AB) |
28.4″ 28.4″ – 32.4″ (19AB) |
27.6″ 27.6″ – 31.6″ (19AB) |
28.4″ 28.4″ – 32.4″ (19AB) |
M | 21.0″ 21.0″ – 25.0″ (19AB) |
21.8″ 21.8″ – 25.8″ (19AB) |
21.0″ 21.0″ – 25.0″ (19AB) |
21.8″ 21.8″ – 25.8″ (19AB) |
4u price list and specification guide 2021 | (1.84 MB) |
4u brochure | (3.73 MB) | |
Copper Mesh Collection brochure | (4.38 MB) |
Education Solutions book | (9.86 MB) | |
Healthcare Solutions book | (15.64 MB) | |
Look Book 2020 | (68.75 MB) | |
Solutions: Seating Collection Overview book | (9.99 MB) |
4u 2D autoCAD files | zip | (4.8 MB) |
4u 3D autoCAD files | zip | (38.51 MB) |
4u revit files | zip | (3.55 MB) |
BIFMA LEVEL 2 certification | (467.46 KB) | |
CLEAN AIR GOLD certification | (441.6 KB) |
4u cleaning and care guidelines | (135.13 KB) |
base to chair assembly instructions | (308.35 KB) |
33A/35A 4u arm with 6 way adjustment user guide | (147.74 KB) | |
38A/38AG Basic height adjustable arm user guide | (148.87 KB) | |
39A roll back arm user guide | (146.55 KB) | |
51A/51AG/52A/53A 8-way adjustable arm user guide | (162.22 KB) |
4u upholstered backs integrated adjustable lumbar support user guide | (145.96 KB) | |
LS4B/LS4W 4u adjustable lumbar support user guide | (148.62 KB) |