The Lisle Heavy Duty Impact Sockets are designed with more than three times the standard socket mass, so they direct more energy to removing the bolt. Available in two options: the 26mm heavy impact socket or the 27mm harmonic balancer socket. The 26mm socket is heat-treated, impact-quality alloy steel that can be used on 26mm or 1" applications. The 27mm socket can be used on Dodge 3.6L engines that use a 27mm hex pulley damper bolt or other 27mm applications.