Problem Solvers Chain Tensioner - 2 Pulley

The Problem Solvers Chain Tensioner is a handy device when you're building a singlespeed bike and need to remove slack in the chain and keep it running smoothly. It's made of light and durable CNC-machined 6061 aluminum with steel hardware and has efficient, long-lasting nylon pulleys. It simply screws onto your frame's derailleur hanger. It even lets you adjust your chainline, too.