Water exercise is a fun and energizing workout that can provide aerobic, strength and flexibility training. The Bintiva aquatic dumbbells are shaped like the weighted dumbbells used for land exercise, but are light because they are made of foam. The weights you use on land work your muscles as you raise them against gravity, but in the water, the resistance is opposite. The dumbbells resist your efforts to lower them. The bigger the size of your aquatic dumbbells, the more resistance they will provide. There are many benefits of exercising with aqua dumbbells. It improves the cardiovascular system and is a great strength training regimen, due to the natural resistance that the water provides.