For large mainline drains, our 11/16” DuraFlex drain cable is available in hollow core, inner core, and oil tempered styles and is used in the Duracable drain machine models DM175 and DM55. 11/16” cable is a great alternative to ¾” sewer cable as it is durable, but weighs less than ¾” cable so puts less strain on the operator. Hollow core is our most popular cable type, however, inner core cable gives the cable a stiffer feel for longer runs. Oil tempered cable is made from a stiff wire that was developed for the auto industry to be used in valve springs. The stiff wire makes the cable stronger and more rigid than standard inner core cable. The oil-tempered cable is used for long, straight runs where there are few traps to negotiate. Because of the strong nature of the material, the cable pushes like a rod through line blockages.