These are top quality, sourced and made in the UK. They have a machined down head so the do not interfere with the 27mm rear hub nut. They are standard length (9mm) and fit with standard lock washers, and also the newer 3 hole type we make (not suitable for the 5mm deep MBD type lock ring, you need to use these for the MB type. They have a socket capscrew head for allen keys to tighten/loosen.