WHB-1 Wash hand basin space saver with self-closing waste valve from McAlpine. 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. Specification: - Size: 1 1/2 BSP female inlet nut x 1 1/4" universal compression outlet; - Designed to allow full use of storage space below the basin within the cabinet or furniture; - 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 - The WHB-1 self-cleaning waste valves have no water seal, so can never dry out through evaporation or lack of use, as the membrane seal remains closed - Overall height 62mm.