Viega ManaBloc® arrive fully assembled and factory tested. They include individual quarter-turn port shut-Off valves, which allow the end user complete control over the entire plumbing system from one central location. Fewer behind-the-wall fittings make it easy to install and less likely to leak. Flexible ViegaPEX tubing in 3/8 and 1/2 in ensures optimal efficiency required to supply fixtures. The choice to install 3/8 in PEX tubing for low-demand fixtures instead of 1/2 in will determine how much water an end user can save with a Viega ManaBloc® system. In a length of 50 ft of PEX tubing, 3/8 in PEX stores only. 32 gal of water (as opposed to 1/2 in PEX tubing's 46 gal). Storing less volume of water means less time is required to purge the line and deliver hot water twice as fast as with a 1/2 in PEX line. Viega ManaBloc® is a complete plumbing system that is easy to install and provides fast hot water delivery by decreasing energy costs and reducing water waste.