The Tractor XL is CNC machined from solid 6061 Aluminum, with a very unique and extremely strong tapered design, starting with 16mm at the core, down to 6 mm at the teeth, which was created for a clean look, to eliminate the need for crank spacers and also have a recess for your crank arm. This sprocket is a flybikes original, very eye catching and will definitely set your ride apart from the crowd. Comes in 25T and 28T gearing\'s only. ###section### Product Specs TYPE: Bolt On MATERIAL: Alloy WEIGHT: 118 g /4.1 oz