Lang Ecotec Serpentine Belt Tensioner Tool Description: Lang Ecotec Serpentine Belt Tensioner Tool is designed for serpentine belt service on Ecotec 2.2 and 2.4L inline 4-cylinder GM vehicles, allows service of serpentine belt without removal of engine mount or lower air filter housing, and allows access to tensioner from top of engine, and double square drive allows improved leverage and flexibility. Lang Ecotec Serpentine Belt Tensioner Tool double square drive allows improved leverage and flexibility in all Ecotec applications and the low profile allows it to fit into space between tensioner and frame rail.