Fit for Taotao Boulder B1,Coolster 3050HD 110cc ATV,110cc Peace Motorsports ATV, and many other model. Caliper Details:Mounting Holes: 2.5″(63.5mm) center to center Brake Line is approx:21.6″(55cm) long. The Assembly has the Rear Brake Master Cylinder, Caliper, and Brake Line Hose. The Compelet Brake Assy is with brake fluid and brake pad installed, 1 more set of extra brake pad as spare parts. parts is a brand that focuses on dirt, bike, ATV, go, kart and other motorcycle powersports accessories.Our accessories include commonly used replacement parts and personalized modifications.We will update our products all the time, and the parts you need will appear in our shop.If you have any questions about the product, please leave a question or let us know by email, we will answer for you.If you have more needs, please let us know by email. We are happy to serve you.Believe me, when you placed your order for the first time, the long story between us is just beginning.