Squire Singlespeed Chainguide (09)
Gusset make budget-conscious but highly durable components, and this 96g alloy singlespeed converter is a perfect example.
It fits a frame with standard dropouts in place of your rear mech and tensions the chain using a coil spring to keep the alloy arm pushing away from the right-hand chainstay.
A jockey wheel running on cartridge bearings keeps the chain running smoothly. You can never quite lose the noise of chain vibration on the jockey wheel, though – it’s no worse than any other converter, but there nonetheless.