The inspiration for the ReAkta knife range came from an enquiry within the construction industry for us to develop a safer knife for plasterboarders / dry lining fitters.  The ReAkta knife is a utility knife on which the blade will stay in the 'out' position with any controlled cutting movement, but retracts if shaken, jerked or dropped.  The ReAkta 'auto-retract' is a variation where the blade will not lock in the out position.  Many other variations are available with different blades and cutting depths.