The Cressi Marseillaise Belt is a stretchy rubber weight belt with holes at regular intervals for best fit. This is fastened by a Marseillaise stainless steel buckle with tilting check pin to facilitate tightening.
Why do we need a stretchy belt? As you descend and pressure on the abdomen and wetsuit compression mean that a traditional webbing loosens. The stretchy belt automatically tightens up during descent to keep that snug fit during the whole dive.