WROT-COPPER and CAST-COPPER Alloy fittings from Elkhart Products Corporation are for use in plumbing and other mechanical applications. All 1/8 - 8 fittings are manufactured in the United States at one of our three locations; Elkhart Indiana, Geneva Indiana and Fayetteville Arkansas. WROT-COPPER fittings are designed to join ASTM B88 and ASTM B280 seamless copper tube.