The best belts are made of stretchy silicone, rather than rubber or canvas. This lets your belt stick tight to your hips, rather than riding up over your waist as soon as you turn upside down.

Silicone belts stick to your weights, making sure they don't slide around when you dive.

A pin-in-hole style buckle is easiest to release one-handed in an emergency.

Canvas scuba belts are cheap, but they fall off easily, let your weights slide around, and will ride up around your waist the first time you turn upside down.

The clip style of buckle releases accidentally more easily than the pin-in-hole style of buckle.

Rubber belts are the older style of freediving belts. They are durable, but not as flexible as silicone, so they won't stick as well to your hips.