The HMX Blue Topaz linear switch comes with a PC top housing, LY stem, and P4 bottom housing. Unlike most PC top housings we have seen, Blue Topaz's top housing is specially molded to eliminate loose top-out sound. Blue Topaz's top-out sounds subtle and concentrated. The P4 bottom housing is made of a new nylon blend material; HMX added less fiberglass and more PTFE to PA66 to create the P4 bottom housing. Unlike your P3 or PA3.0 bottom housing, P4 sounds a bit quieter, and the bottom-out feeling is tempered. However, when paired with the LY stem, I still wouldn't say the Blue Topaz is a deep-sounding switch. It is not as loud and clacky as some other HMX options such as Hyacinth V2, but they still fall into the same category in my opinion.
