SmartLock fittings are a superior product that utilizes metal to metal sealing technology for a more secure and permanent seal, compared to other fittings on the current market that uses rubber o-rings as the main sealing agent. Rubber o-rings deteriorate at a rapid pace once exposed to external environments (refrigerants, oils, temperature, ozone, etc), but metal ferrule does not have those issues at all. SmartLock fittings have the highest design pressure range and burst pressure range on the market. In our humble opinion, we believe SmartLock is the safest opinion available in the market.