3/8-16x1" exactly as described, perfect for lots of stuff on my chopper. Come in bags of 10, so after using 2 for tank mounts have 8 more to use (rear fender mount, exhausts supports, etc.). Will order more fittings from Lowbrow soon! you are the go to guys for folks who like to cut up perfectly good bikes and do weird things to them. Search local hardware suppliers for some of the fittings y'all stock and they look usually look at me like I am nuts.