MMG Gates Powerlink PL20507 replaces 669 18 30 Standard CVT Drive Belt 49cc/50cc GY6 QMB139 4 stroke Engines Gates PL20507 PowerLink Belt replaces Standard Belt 669x18x30 Gates Premium belt provides longer durability for high performance applications. Fits on 49cc/50cc GY6 QMB139 4 stroke Engines