The ST-550 is an adjustable wire stripper to six wire gauges: 18-28 AWG. These Precision Wire Strippers feature an adjustment dial that allows the operator to select one of six different settings. A calibrated wire stop can then be adjusted for the desired insulation strip length. Calibrated Wire Stop adjustable from 0.039" to 2" (1mm to 50.8mm). Clean, precise strip of any insulation type.