The amazing VS-4 Smartvalve is a total revolution in air release valve technology. The twin chamber design overcomes all the shortfalls found in all models of single chamber air release valves especially when used in the sewage environment. All single chamber ARVs are technically designed to fail as the solids floating in sewage are in direct contact with the floats and mechanism of these air valves. Failure rates of 80+% are very common.The VS-4 Smartvalve is designed to overcome these problems and has proven in the field to be 100% reliable and also with a greatly increased service interval saving many thousand of dollars on maintenance costs. More information can be found at www.vs-4.comWith current distribution of the VS-4 Smartvalve in Australia, NZ, USA and the UK the performance and reliability of the VS-4 is well proven. We are currently looking for distributors in all other countries of this amazing planet of ours. Check out the video on the web site www.vs-4.com. Many thanks.