The Skunk2 Racing K-series Timing Chain Tensioner is the ultimate safeguard for all Honda K-series engines. The Pro Series Tensioner body is machined from high-quality steel which allows for greater precision, consistency, and durability over all other tensioners.  They're heat-treated and feature stiffer, OEM-quality springs. These springs prevent the exhaust camshaft from slamming shut at low engine speeds and eliminate chain slack, even under low oil pressure conditions, when the factory spring compromises. The Skunk2 Pro Series tensioner also includes an upgraded, 16mm diameter, tool steel piston (1.5mm larger). The larger ratcheting mechanism features deeper and wider, hardened-steel ratcheting teeth for extra protection.  This advanced design features reduced distances between the front teeth and a larger, more prominent, rear tooth;  resulting in the most precise piston control available. The Skunk2 Racing Pro Series Timing Chain Tensioner is the ultimate fail-safe against excessive piston travel due to worn teeth. Skunk2 Racing's Pro Series tensioner fits tightly against the timing chain guide preventing rotational movement, which bears an uneven load against the ratcheting teeth. The factory-designed oil passages and check valves are retained, maintaining constant, optimal pressure and lubrication as Honda intended. The Skunk2 Racing Pro Series Timing Chain Tensioners have undergone hundreds of hours of engine dyno testing, simulating the most extreme conditions possible, including low-rpm (low oil pressure) testing, harsh engine starts/restart environments, and some of the most advanced camshaft and valve spring combinations only available from Skunk2 Racing.