STANLEY PROTO INDUSTRIAL 3INPWREXT3/8D

The ball detent on the male end is not a ball but a post, that means it won't slide in when you shove it into a socket, or try to pull it out. You have to push it in with your fingernail to get it into a socket, and if it is in the hole of a female fitting you need to find something to poke in the hole to push the post in. The female end has one oversized hole for a ball detent to hold, but no internal grooves on the other three internal walls to hold a ball detent. I'm a tool guy, there aren't many tools I won't keep around just in case I find a use, these are going in the recycle bin.