Check the listing for details. GRAINGER APPROVED 89002 Grip-Neck Stem Caster Socket,Plastic,PK5 19YX21. Condition: New. Listed at 6.06 USD. Grip-Neck Stem Caster Socket, Plastic, 5/16 in Maximum Tube ID, 1 3/4 in Overall Height, For Stem Length 1 1/2 in, For Stem Type Grip Neck, Package Quantity 5 Sockets for grip-neck stem casters press into drilled holes in wood to provide a secure mount for attaching grip-neck stem casters with a 7/16"-diameter stem to the wood. The socket mates with the stem of the caster to hold it securely in place. These sockets are used for mounting grip-neck stem casters on chairs, tables, and other light-duty equipment that have legs made of wood.Stem caster accessories are used to install and remove grip-neck stem casters and friction-ring stem casters from furniture and equipment. They include sockets and brackets that are designed to mate with the stems on the casters to hold them in place. They a.