Delchem Dual Flush WC Cistern Syphon 7 1/2" High. Variable flushing volumes. 6 / 7 or 9 litres at full flush allows you to set the volume of water flushed to clear the WC pan, also has internal overflow, should the cistern overfill excess water will drain into the WC pan. Standard 1 1/2" outlet.
How the dualflush operation for this siphon works:
The full flush volume is achieved by flushing the WC in the normal fashion of fully depressing the lever and immediately releasing once the flush has started.
The short flush volume is achieved by fully depressing the handle in the normal fashion and holding the handle in the down position until the flushing cycle has finished.