Filled with Metal sand Nylon cover velcro straps with metal hooks.

Ankle weights do increase your overall endurance. This is because adding additional weight forces you to exert extra force than usual thus increasing your endurance and helping you with other benefits such as cardiovascular and pulmonary health. Within few weeks of the use, you start building more and more stamina.

Leg raises without any resistance can shape your legs but to further enhance your workout you must add more resistance. Doing just more reps may not be as effective as you think they might be. To grow your muscles stronger, you must add weight. If you consistently workout with more weight you would eventually start seeing the leg shape you desire

Sells as each, not in pair.

Ankle Weights - Sports & Fitness