Review on Lifegard Aquatics Double Threaded Bulkhead: Enhanced Hydraulics, Pneumatics & Plumbing Solutions by Matt Kucrud

I bought four of these and was able to use two. However, the two I used were easy to screw on and off, the other two required me to use channel locks and a pipe wrench just to get them apart. They could not be used once inserted into the barrel. Not sure why half of these fittings were so difficult to unscrew while the rest worked great. I now have to buy another pair and will certainly not buy these again. Hope that helps