The backrest and side support may be rotated through 360° and raised to a maximum height of 267 mm (10.5”) above the seat or lowered to a minimum height of 60 mm (2.25”) above the seat. Alternately the entire backrest assembly can be demounted. Width between the arm rests is 585 mm (23”). The dimension from the center of the seat to the backrest is 410 mm (16”) this dimension can be reduced to 444 mm (17.5”) by fitting the cross-member in front of the column and swapping the tube member round.