Whether you're snorkeling, scuba diving or free diving a good pair of fins is a must-have.

Buckle/Strap System Easy-adjust buckles with rubber straps are standard. However, these days manufacturers and divers are replacing them with bungee or stainless-steel spring straps that eliminate the need to adjust your straps. They also make quick work of donning and doffing.

Foot-Pocket Design Closed-heel foot pockets are worn barefoot. They are thin and flexible and very comfortable, but proper fit is critical. Open-heel fins are worn with a bootie. They are more forgiving of fit because they can be adjusted with a heel strap.

Blade Design Long, stiff fins look cool, but they require more kicking effort, and can put stress on weak muscles. More-flexible fins are much easier to kick, and often produce more propulsion for the amount of effort expended.

Materials Fins made of thermoplastic elastomers tend to be lightweight and rather stiff. All-rubber fins tend to be flexible and rather heavy. Many fins are made with a combination of the two, using plastics for stiffness, and rubber for flexibility and foot-pocket comfort.

Maintain your fins with these tips: How To Care For Fins.

If you're in the market for new fins, check our Dive Gear Review: Fins.

Are free-diving fins right for you? What You Need To Know About Free-Diving Fins.