Wash Hand Basin Space Saver with Self-Closing Waste Valve - 1 1/4" BSP female inlet nut x 1 1/4" universal compression outlet. Additional features: |The internal membrane opens under water pressure to allow discharge to flow freely and then closes to form a seal to prevent foul odour or sewer gas entering the building. |The valve allows air to be drawn into the discharge waste pipe when negative pressures occur and eliminates the need for secondary ventilation to the discharge pipework. |This allows for greater flexibility in the plumbing design. |The valve can be easily cleaned without having to disassemble the discharge pipework. |Simply remove the split pin at the front of the valve, take out the plug and membrane and clean in hot soapy water. |Reassemble and relocate the split pin in the slot provided.