Shank size - 1/2" , thread size - 13, length is 1.75".  Very sturdy.   For square top machines such as but not limited to VF-56, VF-63, V-63, VF-90, V-90, VF126, Cavalier CSS-64, CSS-64G.  For Cavaliers we suggest you check the size of the ones on your machine to confirm size.  Second picture shows our new one next to an original to give you a better idea.  Sold individually - order as many as you need.