The Problem Solvers Backstops are frame mounted clamp-on housing stops featuring two cable routings with slots.The Backstop was originally designed to replace cable guides by adding cable stops on the top tubes of old frames to allow the use of linear pull brakes. The Backstop now features the option of one or two cable housing routings along with slots for easy installation, removal, or applying lube to the cable system.The Backstops can be helpful for unique setups such as routing cables on bikes that don't have stops but are using derailleurs or internal hubs. An example would be running a 3 speed or Rohloff hub on a Surly 1x1 or other dedicated single speed.Problem Solvers gives you more possibilities for setting up your bike the way you want it.Technical details:Machined and anodised 6061-T6 aluminum, hinged clamp and stainless 5mm mounting bolt,Features two cable routing options with slots for easily installing and removing cable housing,Fits only round frame tubes and designed for the top tube,Available in 1-1/8", 1-1/4", 1-3/8" and 1-1/2" inner diameter.