BSP Adaptor Female/Female Couplers Series 2543 Can be used with rigid PA tubes. A locking nut is provided and can be tightened both manually and with a spanner. The special shape of the guiding cone ensures that the tube cannot be accidentally cut. Material: OT58 (nickel-plated). Threads: GAS conical ISO 7 (BSPT). GAS cylindrical ISO 228 (BSP). Pressure: 40bar. Fluid: compressed air or other low pressure fluids. Temperature: -40°C to +120°C.