WRAS is the water Regulations, they pass approved fittings, due to a lot of imports being made with sub-standerd materials that could cause contamination to the water supplies, if traced back to you or person who fitted them them a very large fine could be imposed, speak to your plumber about it ! Myself I will-not fit non-approved materials, Thats you, and your plumbers choice but on your head be it! Just because its WRAS do's not mean that it costs more.