Judging from the picture, it appears to be a 1/4", but if you're concerned about the proper leg length, take a look at your guitar's pickup cavity. If it's quite generous (and that's quite rare), go with the 1/2". If you're unsure, it's best to shoot Tim an email or give Bare Knuckle a call in order to be sure. If I'm not mistaken however, the only guitars that ever use the 1/2" are vintage Gibsons.
