I've been wanting one of these for several years. I finally got my hands on one when fithops generously sent me one to leave a review for. I wanted to leave another, more in depth review after testing them for several months. I now own several different variations and all the attachments for them. The imagination runs wild with these trip alarms. They work well with blanks but I really like the 209 shotshell primers since they are so small and packable. The machining/fit and finish on these is very nice for the money you spend on them. More often than not (especially these days) the machined products you buy aren't even deburred, but that's not the case with any item I've gotten from fithops. The coating on every moving part is evenly applied and well adhered. It's not going to flake off and let things rust. The spring tension is high enough that you don't have to worry about light strikes, and the action is easy to set so you don't have to break it in before you can trust it. They offer several ways to attach to various objects, and offer the versatility to think outside of the box when setting up trips in most scenarios you can think of. Overall I'm very happy with my trip alarms and I bring at least one with me every time I hit the wilderness. Usually the small one designed for the 209 primers. But as a machinist, I love the fact they put threads on the gen4, as now I can make things that thread into the end of it, to increase the versatility even more if I needed to.