The nuts feature a self-locking design, so when they are fastened to a stud by hand, they will stop when they reach the "locking" portion. You will then need a wrench or socket to fasten it further, at which point it will "lock" in place.
High Strength 2 X Exhaust Studs Nuts 42mm Long
4PCS Exhaust Studs & Nuts Kit For Big Twin 1984-2015 Sportster XL 1986-2014
42mm Exhaust Studs & Nuts 1.5
42mm Exhaust Studs & Nuts M10x1.5
2 EXHAUST S NUTS SET 1.5 X 42MM LONG
