The PVB-CB-12 three star black Buna-N Static safe (10 - 10 ohmssq) non-marring angulated 30 probe (working temp. -5 to 250 F) is .5 in diameter. It is for use on all our vacuum tools with the exception of the Roto-Pic and PV-500.Specs amp; FeaturesProbeCupApplication: Bent probes offer improved visibility, Quality: , Surface Resistivity : 10-10 ohmssq, Shape: Bent Tip, Tip Angle: 30, Material: Black Buna-n, Tip Width: .5 (12.5mm) dia.