Posted By Simon Wakeham They are very difficult to use and the results you get from them can only be used as rough guidance. The amount of vibration actually transferred to the person using the equipment can vary dramatically from use to use, so the only way you'll get an absolute record is by hooking them up everytime the equipment is used. The way the vibrating tool is gripped and used, are parts worn etc can change the rating which adds to the un-reliability of your results. I would suggest you focus any efforts into reducing usage levels as much as you can, and base any calculations on the manufacturers infomation, as they're likely to be as reliable or realistic as you'll get using a dosemeter. I hope this helps Simon