The OTC Belt Tensioner Compressor, No. 6725, is designed to compress the belt tensioner spring during engine drive belt replacement and starter generator servicing for easier exchanges. For use on 2.4L GM eAssist engines found in 2012-2016 Buick LaCrosse, 2011-2014 Chevrolet Malibu, and 2012-2017 Buick Regal.