GS Series filters are made by high quality laminated fiberglass and they are 100% factory tested to ensure every products met the NSF50 standard. With fiberglass through out the body, inside and out, means they are reliable and suitable for all-weather performance. Features and benefits: Made to last- Full laminated fiberglass tank with gel coat smooth finish- UV resistance surface to work under the Australian sun – Stainless steel pressure gauge- Metal components are made b