5/16-32 x 5/16" x 3/4" Aluminum #10-32 Threaded Spacers SPCR-137 (8 pcs.)

Diameter: #10
Diameter 2: 5/16"
Length: 3/4"
Material: Aluminum
Thread Size: 32 (Fine)
Style: Threaded
Type: Spacer

Box of 8.

A spacer is generally something used to create a space between two objects, often to properly position them.