The SilverBack XL flexible coupling from Source One Environmental is designed to create permanent pipe connections in pipe bursting and ramming applications. Made of flexible PVC, a heavy-duty shear ring enables the coupling to resolve alignment problems while resisting heavy earth loads and shear forces in 4- by 4-inch clay-to-plastic, 6- by 6-inch plastic-to-plastic and 6- by 6-inch clay-to-plastic connections (custom sizes available). 877/450-3701; www.s1eonline.com.