ITEM NAME:Speed Training Resistance Parachute - Small (40inch Size), 15 lbs of resist K1W4 Speed Training Resistance Parachute - Small (40inch Size), 15 lbs of resist K1W4 40inch diameter, Also available in Medium (48inch) and Large (56inch) 15 lbs of resistance Fits all sizes (up to a 42inch waist), Quick Release for overspeed training. Fully functional unit includes parachute and belt. Suggestion:long-distance running. When you use the drag chute to exercise, the resistance of the air will produce an backward drag force, so the faster you run, the greater the drag force. Through this exercise, can improve the ability of the user's acceleration, muscle endurance, and enhance the ability to adjust the direction of the high-speed running. Material: Polyester Package Included:1 x 40inch Resistance Parachute Note:Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.