ZSDTRP Motorcycle PHBG Manual Pull Choke Automatic Choke Assembly For PHBG 16AS 21AS 21DS 21BS Carburetor PHBL PHBH This choke assembly is designed for use with PHBG series carburetors including models 16AS, 21AS, 21DS, and 21BS, as well as PHBL and PHBH carburetor types.It functions as a manual pull choke or automatic choke system to assist in engine starting by enriching the fuel mixture during cold conditions.The unit installs directly into compatible carburetor setups and provides for motorcycle engines requiring choke control.It includes all necessary components for installation and is engineered for consistent performance in varying operating temperatures.Important: This is an independent aftermarket part.Brand/model references serve only to show compatibility.