RBM 700 Series Model RBM 721 RBM 760 RBM 765 RBM 767 RBM 768 Seat Depth 430 mm 460 460 mm 480 480 Seat Width 400 460 460 480 480 Back height 270 280 400 500 690 Back Width 400 450 450 470 470 Choose from the following models Model RBM 721 £363RBM 760 £539RBM 765 £467RBM 767 £493RBM 768 £588 Armrest (not for RBM 721) Armrest type NoneSideways and height adjustable foam armrest (+£83)Armrest with soft rubber top (+£77) Adjustable lumbar support (Not for RBM 721) (+ £58) Choose from the following Fabric colours: BlackNavyRoyal blue