I had a batch of flanges made with cost being top priority, and this is what I got. They have been used to make working, leak free headers, but you should expect to put some work into the flanges. Made for 1 5/8 primaries, but the holes were plasma cut quickly and angled in, creating an oversized 1.5" hole on the head side and a little over 1.625 on the other. Buy in qty, get them cheaper.