The Protostar is made of plastic, but is designed to overpower most metal yo-yos on the market. It is recommended to buy extra strings. If you play a lot, there will be wear on your string, so that some tricks will not work as well anymore. Weight: 66g Diameter: 56.1mm Width: 42.8mm Gap Width: 3.8mm Bearing: CBC Large Center Trac Bearing Response: CBC Large Slim Pads