ATR it is a Rebel DFNDR9. they say you can use it on anything from 17 HMR to 338 lapua I have used it on .22LR, 300 BLK , 9MM and 308 win. one of the better priced suppressor at $300.00. easy to take apart and clean. and I found the guys at Rebel are great to work with. thought I had a problem with the thread's in my 1/2x28 adapter, called them to make sure of the threads and they where going to send me another adapter no charge, told them to wait, turned out to be boogered threads on my barrel. fixed that by running a die down the threads, no problem now.