I bought these to use with my Align version of the Gaui100/TREX 250 skid mounts. But they don't fit. They are 3.75mm thick and the Gaui100 skid mount requires 3.5mm thick. I also bought a set of 203260 pipes (not here) and they are even thicker, 3.95mm. So I have ordered 203183, HK's version of the Gaui 100 & 200 landing skid set in order to use my extra pipes. This is ridiculous. Make the pipes to fit the stock parts, not make up your own specs.