Designed to fit struts with that use 3/16"(.187) prop shafts, but has the stepped down 1/8"(.125) end to allow use of the smaller 1/8" prop shafts. Specs:Length: 2.25" long (57.1mm)Material: Stainless 303Bored to fit .150 flex cable.Requires:.150 flex cable Part# oct-oc4d Drive DogPart# oct-oc4pn Bullet Prop Nut.146-.150 Flex Cable and installation.