XMark Fitness Rubber Hex Dumbbell Pairs and Sets XMark Fitness, Premium Quality, Rubber Coated Hex Dumbbells. Exceptional quality best describes XMarks rubber hex dumbbells. The one-piece high quality cast iron heads have been press fitted and welded to each handle. A tough, premium rubber casing made from virgin and recycled rubber covers each cast iron head. The chrome plated handles are ergonomically designed to fit comfortably into the palm of your hands. It is no secretXMark dumbbells are higher quality. To reduce costs, all of our dumbbells are sold and shipped in pairs or sets. It is a lot cheaper to ship a pair of 30-pound dumbbells instead of two singles. Save some money today. You will not regret purchasing XMark dumbbells. Our team will greatly appreciate your business. Thank you for choosing XMark.