Choosing the right freediving fins is an important step in the sport. The best choice will depend on your needs and skill level. There are a wide variety of models to choose from. These vary in stiffness, material, and price. You can also find models with interchangeable blades.
Some models have rails along the edge of the blades. These help channel the water, but do not interfere with blade flexibility. These rails should start at the foot pocket tendons and end at about 1.5 cm above the v-tip. This is to avoid slipping.
The Omer Stingray fin is made of high quality carbon fiber and has three stiffness levels. It is also lightweight and durable. Its rails are designed to channel water and give a powerful kick. Its foot pockets are made of thermoplastic rubber and are very comfortable.
For beginners, it is recommended to get fins with soft blades. These will be less expensive and allow you to practice perfecting your fin technique.
For advanced divers, carbon fiber and fiberglass are good choices. These are sturdy, durable, and will last for a year or more. Fiberglass models are not recommended for snorkeling or spearfishing, but are great for reef environments. The hardness of the blade will determine its strength.
Some models have separate foot pockets, and other models are glued to the blades. You can also buy modular bi-fins that have separate foot pockets. They can be purchased separately or with the blades.