Leveling glide mechanism, inside side panels are slotted for shelves and accessories, shelves can be added as will, knock down structure, doors can be added later. Note: Swing door cabinet, sliding door cabinet, glazed door cabinet, roller shutter door cabinet and open shelf cabinet can be combined as will. Model and size: C5OP21--W900*D450*H2100(mm) with 4 adjustable shelves. C5OP17--W900*D450*H1785(mm) with 3 adjustable shelves. C5OP13--W900*D450*H1355(mm) with 2 adjustable shelves. C5OP10--W900*D450*H1050(mm) with 2 adjustable shelves. C5OP09--W900*D450*H900(mm) with 1 adjustable shelves. C5OP07--W900*D450*H745(mm) with 1 adjustable shelves. C5OP04--W900*D450*H450(mm) with 1 adjustable shelves. Option accessories: Pull-out desk top, pull-out frame, pull-out drawer, hanging rod, cloth hanging rod, divider, pigeon hole.