The ZS is engaged onto the line manually and is impossible to release by accident under load. As a result the Zs has been designed for ultimate holding power without the easy release compromise of a conventional clutch.

For current rope holding on yachts, clutches are no longer the complete solution. Smaller line diameters, low stretch halyards, sails and stiffer hulls are transferring much higher loads than most clutches can handle. Apart from the XX clutch, the ZS jammer is the only rope holding device that will hold high tech rope at its safe working load. All ZS models do this, even at sustained extreme loads to 12000kgs (12 tonnes) on 32mm (1/4") line, with zero rope wear.

The ZS is highly recommended for larger diameter lines and for extreme loads where always having to use the winch for release is a positive safety feature.