It is not suitable for tubing with metal casing. FESTO Tube Cutter. The pipe and tubing cutter ZRS is used for cutting plastic and nitrile rubber tubing, up to Ø 20 mm, with or without textile insert. It also has an integrated safety catch to prevent unauthorised opening. Features and Benefits. For cutting plastic and nitrile rubber tubing Outer diameters up to Ø 20 mm RoHS-compliant