PARIKHS LuxLock World's most secure USA Patented Replacement Earring Back White/Yellow/Rose Gold. PARIKHS LuxLock World's most secure USA Patented Earring Back Pair with comfort disc in 18k Yellow gold (Patent # US8365369). Easy to handle and provides close and secure grip. It is used for Friction Back stud. It's surgical stainless steel mechanism guarantees strength.