The bolt tensioners are designed for quick and accurate tensioning of pipe flanges etc. in a subsea environment. The tensioner has a minimum of parts to enable fast and simple attachment to studs where visibility is poor. Quick fastening reaction nut: allows rapid tool application and removal regardless of bolt length, corrosion or thread damage. Unique floating piston design: tilts in any direction without loss of load, eliminating piston seizure and aiding tool retraction. The Subsea tools are safe and easy to use.