Gel filled wrist support offers comfort and support to any work surface of keyboard trays, and feature anti-skid bottoms. Gelfoam is a unique innovative compound which offers the soft-touch feel of gel, combined with the anti static & durable properties of molded product. WR-GFO1 Gelfoam 20" notched bottom Fits model AKT2M Tango WR-GFO2 Gelfoam 20" flat bottom WR-G27 Gel filled 27" flat bottom Polyurethane surface GRO363 Black ABS plastic 3 3/16" (80mm) diameter GRO924 Black ABS plastic 2 3/8" (60mm) diameter back to top