Extra large gas purifiers (750 cc) are ideal for bulk purification applications or where several instruments are plumbed from a single gas source. They provide a low cost alternative to UHP grade gases. We construct each trap from one piece of heavy walled aluminum tube to eliminate potential leaks due to faulty welds. The moisture and hydrocarbon models can be refilled. The big oxygen traps must be replaced, but we offer indicating oxygen traps that can be installed downstream to show when it's time to change the big traps. All models are available with a choice of 1/8", 1/4" or 1/2" Swagelok TM tube fittings. We purge each trap with an elevated temperature, UHP grade helium (nitrogen or hydrogen purged units are available upon request) and leak check every unit.