The 159B-RTX replacement tips for 159B-RT contain 2 tips and 4 screws. The Carbofib tips are a polymer based material with 30 carbon fibers added (conductive 10 ohmssq). Carbofib has very high rigidity, excellent tensile and flexural strength, fatigue and creep resistance, and temperature resistant to 249F. Specs amp; FeaturesMedium Points, Soft Replaceable Tips, Application: Replacement tips for 159B-RT , Quality: , Surface Resistivity : 10 ohmssq, Shape: Straight, Material: Carbon Fiber Tips, Tip Width: .04 (1mm), Tip Height: .038 (.95mm)