Recently purchased a Rated PR valve that has 1/8th inch pipe external threads and is set for 100 psi from MSCdirect.com, item is all brass and goes off at the 100psi rating. Item number is 08059909 and is mfg. by Kingston with their part number of KSV10-1-100, located on page 4001 of MSC's big book catalog. Unit measures 1.5 " in length x 5/8th" in diameter. Price of unit is currently $10.06/unit plus shipping. MSC's shipping is quite reasonable for most items.