Triton Audio FetHead Phantom by Dohreetoh
I bought this a while ago to use with mics with mics with less than great self noise so I wouldn't have to turn my interface preamp up too much which would add extra noise.
It gives the mic 18 dB of "clean gain". It works well and it is quiet, and I don't think it noticeably colours the sound. Clean gain is in quotes simply because these devices (barrel adapter preamps) usually use that phrase in their product descriptions. There's not any noticeable self noise coming from it when amplifying a mic (which makes sense since the entire point of it is so you don't have to crank your mixer or recorder pres). Of course there are also a lot of built in interface and mixer pres that also have low self noise when turned up a quarter of the way (let's say that's 15 dB of amplification for argument's sake). So take this whole "clean gain" claim with a grain of salt.
It's really easy to use, just plug it into the mic's XLR jack, plug the XLR cable into it, and turn on phantom power. It boosts the signal a lot. It's actually pretty easy to get nasty feedback if you turn the interface/mixer gain up too much.
I think it is good value for the money, but only if you buy one. Once you but two or more, I'd say something like the Line Audio 2MP would be better value (at the time of writing this, 2500 SEK converts to about $270 USD, so it's like $135/channel and the Fethead Phantom is around $100 itself and provides nowhere near as much gain), as that can add 60 dB of gain. Of course the Fethead Phantom would still serve as a good option for location sound guys. But if you're considering a couple of them in a studio environment, I'd recommend something like the Line Audio 2MP, or any other similar preamp (i.e. good sub $300 pres with 2 channels) that can add more gain than the Fetheads and other barrel adapters.