SODIAL(R) Blue Rubber Bulb 0.9" Diameter Plastic Clasp Horn for Bike Bicycle Bike Horn Fit Clasping Item Dia. : 2.3cm/ 0.9" Reed Bulb Dia. : 5.2cm/ 2" Horn Open Dia. : 7cm/ 2.7" Total Size : 15.3 x 7.2 x 7cm/ 6" x 2.8" x 2.7" (L*W*H)