tm-405 tm-4001featuresdisplay : 5 digits, 10mm (o.4") lcd (liquid crystal display)multi functional, one instrument combines photo tac (rpm) bi contacttach (rpm, mmin. ftmin.mod:tm 4005)widemeasuringrange.the last value, maximum value, minimum value is automatically storedin memory and can be obtained by pressing memory call button.high vlslble, insignificant zero suppression lcd display gives exact rpm withno guessing or errors and saves battery energy.tm 4005 & tm 4001 tachometer used the exclusive one chipmicrocomputer lsi - circuit and crystal time base to accurately offer thehigh accuracy measurement. _the use of durable, long - lasting components, including a strong, lightweight abs-plastic housing assures maintenance free performance for manyyears.thetachometer housing is shaped carefully can easily fit ln elther hand.