Yany Metal Smart Balls.The first metal Kegel exerciser in the world. High quality Silicone wraps the luxurious metal balls, gives the user a better experience. The set comes with 2 sets of high quality aluminum balls in 1.06 ounces balls in Gold color and 1.41 ounces balls in Blue color. Specifications Kegel Ball material metal. Belt material Silicone. Weight Gold Kegel Ball 1.06 ounces, Blue Kegel Ball 1.41 ounces. Overall dimensions diameter 1.21 inches, length 6.10 inches.