HIGHCHAIR SLIDING TRAY HARDWARE Arm Piece - 6" long x 5/8"wide x 7/8" deep Tray Piece 3 5/16"long x 1" wide x 15/16" deep Best for use with our W3-5226 Grooved Trays or similar styles only. Comes as a set for attaching one high chair tray. Long piece attaches to outside of arm. Short piece attaches to the underside of the tray. Spring loaded clamp allows the position of the tray to be adjusted then locked into place. This style of hardware began to appear on high chairs in the 1940's.