1/4-28 Thread. Shape is round nose bullet spinner. OD: 1.25" (31.73mm). Length: 1.177" (29.9mm). 5/32 to 3/16" or 4mm music wire and 5/32 or 4mm Allen wrenches are ideal installation tools. Stock photo from Dubro. Item is 1 spinner nut only. SKU Number: DUB730