Dimensions (Overall): 2.8" Dia. x 6.5" H (71x165mm)Outer Probe Diameter: 2.5" (63mm)Inner Probe Diameter: 1.2" (30mm)Insulative Resistance Between Probes: > 1x10(12) ohms @ 500vProbe Resistance Of Carbon Pads: < 100 ohms @ Low Test Voltage