The RT-3 Wrist Strap Checker is an easy-to-use hand held tester for all types of single wire wrist straps and ground leads. It is a compact, portable unit that reliably indicates the condition of the wrist strap, ground lead and interface to the user’s skin. If system resistance is too high (>10 megohms) or too low (< 800 kilohms) an audible alarm will sound and either the high or low indicator will light. If system resistance is within the satisfactory range, the "OK" indicator will light. May optionally be placed in series between ground and wrist strap for convenient periodic testing without disconnecting wrist strap.