Ralston's Series 5000 is made from prime polyethylene resin in full 6 mil gauge (150 um) for stock sizes. Custom gauges are also available. This is a special purpose construction film to be used as a long lasting vapour barrier within wall cavities and is designed to exceed the criteria specified in C.G.S.B. Standard CAN/CGSB-51.34-M86. Ralston was the first Canadian manufacturer to be awarded CGSB status on this product.