Best silencer under $150

Last time I checked Krale no longer sells LDC's to U.S. customers. Too many of them were being confiscated in customs because they don't know the difference between airgun moderators and firearm silencers.

Other Hatsan owners should chime in here, but I tried to help a friend who wanted to use a different brand of 1/2" UNF airgun moderator on his Hatsan and it left a gap at the muzzle because his Hatsan moderator is made to thread over the barrel somewhat like the Daystate reflex carbon fiber moderators fit on a Huntsman Regal barrel.
 
Donny's incredible to deal with and makes a great product, but my Hogan Decimeater is smaller and quieter than my Sumo and half the price.

I have both the decimeter, weihrauch, and also the Donny FL tatsu. On the decimeter and weihrauch I can hardly tell the difference soundvise and both have the same quietness on all my FX guns in caliber .177, to .25. I use the decimeter on the .25 cailber as the hole in the baffles is bigger than on the weihrauch. There is nothing wrong with the DonnyFL tatsu, I bought is as I wanted to try a relative short one on my 700mm .25 barrel. But it is to load for my taste, so I kept using the decimeter instead. I can not speak of the other models though.
 
I can't say enough kind things about Donny!!!! He is a class act and even turned down a sale to me for his largest model b/c he said it wouldn't make my gun any quieter (noise was from hammer bounce). Who does that? 

I have purchased three of his moderators in the past few months and I will be buying more from him in the future; not because I need more of them, but b/c he is such an honest guy that I want to support his business. Oh and yeah, mouse farts coming out of my guns now.
 
I always see a lot of post on Donnyfl mods that almost look like adverts for a team, lol. I'm sure he is a great guy as well as the other manufacturers. I had a Sumo and bought an STO Pilum, they were both very close to the same db. I kept the STO as it was lighter. The Sumo did look a little nicer though but it is on the end of a Dreamline so I didn't want the extra weight on the barrel.
 
I bought a DonnyFL Ronin for my .25 Hatsan BT65. At 1st I wasn't impressed as I removed the shroud & screwed the Ronin directly onto the barrel. No quieter than the factory shroud. BUT THEN I got the adapter that allowed me to screw the Ronin to the end of the shroud. Yeah, it made the gun 6.5" longer but WOW did it quiet it down! The hammer spring ping was louder than the gun's report. Not only that, but the extra length made it MORE ACCURATE!!! Don't know if you have a QE (quiet energy) BT65 but, based on experience, I'd say go with a Donny! Call or email him. He's great about getting back to you quickly, maybe in minutes. He'll answer any questions. Good luck.