A versatile range of resistance boxes available in 5, 6 & 8 decades. High Accuracy and wide range 0.001 ohm to 11 Megohms are combined in a compact lightweight case. The switches have gold plated contacts to ensure a low contact resistance and negligible thermal E.M.F. Some models employ the Waidner Wolf technique to eliminate the errors that may be caused by the variations in switch contact resistance. These models are particularly suited to applications such as Pt100 simulation where resolutions as low as 0.001 ohm are required.