The 331A three star fine straight stainless steel probe has 10 mil tip and is designed for work under magnification. The overall length is 3.Specs amp; FeaturesShort Fine TipApplication: Ideal for work under a scope, Quality: , Surface Resistivity : Conductive, Shape: Straight, Material: SS, OAL: 3 (75mm), Tip Width: .01 (.25mm)