Premium Neoprene ATTENTION - The elastic of this weighted vest should be at the waist. Please look carefully at the direction of wear on the pictures MADE TO LAST - Made of premium chloroprene rubber for comfort, this weighted vest stays super rigid, breathable, soft and elastic even under extreme conditions, ideal for all sports lovers STUFFED WITH IRON SANDS - Stuffed with chemical-free iron sands, this weighted vest is suitable for strength training, muscle building, stair climbing, weight loss, weightlifting, walking, running and more, helping improve cardio conditioning and body strength, giving you more power, speed, and agility DOUBLE ADJUSTABLE BUCKLE STRAPS & REFLECTIVE STRIPS - The integrated adjustable buckle strap is suitable for bust between 35~45 inchs; elastic edge of this weighted vest provides superior flexibility for workout, accommodating users of different sizes; reflective strips on both sides of the weighted vest keep you away from traffic accidents in all weather conditions(rain, fog, dark) at day or night FINE CRAFTSMANSHIP - Double stitches craftsmanship prevent sand leakage; thickened & widened shoulder delivers weight evenly and avoid shoulder fatigue, delighting your workout with ultimate convenience