LHP-1 is an optional device for HPW-2 the handpiece counter to measure lower revolution from 1 to 5,000 rpm.
LHP-1 is an optional device for HPW-2 to measure from 1 to 5,000 rpm. Just connect HPW-2 and LHP-1 with the relay cable, then it is ready to measure low rpm.
LHP-1 does not make a simulated measurement of handpiece motor rpm electrically, but measures directly the actual rpm speed. Thus you can control your handpiece speed more accurately.