Kinugawa chain tensioners - pair (NJS certified)Budget priced, simple, but effective! Mr Nagasawa includes these with the frames he builds for pro riders.
They fit both 110mm/8mm and 120mm/10mm track frame ends and are sold in pairs. Made in Japan, and NJS stamped and approved.
MKS chain tensioner for aluminium frames - CA-MX10If you have an aluminium frame which has thick end plates, you need these chain tensioners, and not the NJS type. The NJS type only fit on steel frames. Learn MoreUSD$16.50
MKS Chain Tensioners (Mikashima CA-NJS)Chain Tensioners, for 120mm rear spaced track frames.
These help set and hold the chain tension on your track frame, and are used by Keirin pro track racers in Japan.