The Lisle Fuel Filter Plug for Duramax, No. 57170, is designed to be used to plug the fuel filter when changing the filter on 2004-2016 Chevy Duramax trucks. The plug threads into the filter for a secure seal, allowing the fuel filter to be removed from the tight space without spilling. It is made of glass filled nylon for strength and the T-handle makes removal and installation easier, says the company.