The CB-18 black Buna-N non-marring vacuum cup (-5 to 250F) is .13 in diameter. It is for use on all our vacuum tools with the exception of the Roto-Pic and the PV-500.Specs amp; FeaturesCup, Heat Resistant (250F), Application: Designed for high temp, non marring applications - ESD Safe, Quality: , Surface Resistivity : 10-10 ohmssq, Shape: Round, Trade Name: Penvac , Material: Black Buna-n, Tip Width: .13 (3.25mm) dia.