Features: 1MAXIMUM DURABILITY: Aluminum alloy material with surface oxidation treatment to ensure maximum durability 2EASY TO DISASSEMBLE AND ASSEMBLE: Easy to disassemble and assemble, including 20+60 teeth synchronous wheel and 2 synchronous belts 3WIDELY USED IN MECHANICAL TRANSMISSION: Widely used in mechanical transmission occasion such as milling machines, gear forming machines, drilling machines, hobbing machines, etc. 4RELIABLE AND DURABLE: Synchronous wheel is easy to install and disassemble, reliable and durable in use, very practical 5REPLACE OLD OR BROKEN ONES: Aluminum alloy timing pulley is good to replace the old or broken ones and renovate directly Package included: 2 x Big Synchronization Wheel 2 x Small Synchronization Wheel 2 x Closed Loop Belt 4 x M4x4 Screw 1 x Wrench