 type is the spring-top variety with the rubber seal and metal fastenings. If under pressure, the jar will 'burp' itself without letting air inside. It is a simple, no-fuss option. Although the steel clamp/hinge assembly rust overtime (living on a boat doesn't help). Once in a while, we remove them and clean off the rust using our electric drill equipped with a brass wire sbrush. If the steel is too far gone, it may be possible to source some online using keywords like "Replacement Bale-Wire," "Replacement 