Goldstrike Perch Mounted Drink Holder The Goldstrike Big Ass Drink Holder is the perfect way to bring that 30 oz. tumbler on the road with you. The durable neoprene rubber molded net is designed to securely grip your cup so there's no worry of losing it. The rubber is also weatherproof and won't deteriorate in the sun or elements you encounter on the road. Features: Black accent finish Designed to work with 30 oz. tumblers and other large bottles and cups Made from durable neoprene rubber to grip and last Mounts quickly to Ciro's line of ball mounts Features a 4-1/8 diameter opening