The Universe-36 can be used on almost any caliber from 22LR and 5.56 to .338 Lapua and everything in between - as long as it fits down the bore it's good to go. If you want to use it on a 9mm handgun, it can do that. If you want to use it on a full auto 5.56 SBR, it can do that. If you want to use it on a 30-30 lever gun, it can do that. If you want to use it on a 338 Lapua magnum shooting 2000 yards it can do that too. This is for the person who just wants one suppressor to do it all. The Universe has Infinity DNA being DMLS printed out of Inconel. FRT, easy. Full auto, easy. Belt fed easy. It uses a cool end cap system that lets you adjust between low back pressure and high back pressure for any caliber or gun you're using to get it dialed in. Combine that with the fact the Universe-36 also utilizes the universal HUB/1.375x24 thread pattern to let you use any mount, QD system, booster or 3 lug you want. It comes in the box with a 9mm low back pressure end cap installed. Additional end caps that are available for purchase separately: 9mm high back pressure, 7.62 low back pressure, 7.62 high back pressure, 5.56 low back pressure, 5.56 high back pressure. The end caps can be changed with nothing more than a socket OR adjustable wrench, whichever you have laying around. No proprietary tools are needed for this suppressor to ensure it's as easy to use as possible. Otter Creek Labs UNI36 Universe-36 1.5" Black Inconel.