Duo and Mono series multi-stage tensioners are versatile and reliable hydraulic bolt tensioners suitable for high load and tight space applications. Duo tools feature multiple hydraulic stages to give a small tool diameter to fit into tight radial spaces. Mono tools feature low height profile to use when there are overhead obstructions.

Optimised for use on wind turbines they have been designed for long-life, low-maintenance use and are suitable for use on single bolts, or grouped together for multiple tightening of bolted joints. Duo and Mono tensioners are extensively used for slewing rings, powergen applications, structural and all critical bolting.