Got one yesterday. Really feels good in the hand. Shot with it out of the box. Hit a bit high but groups were tighter and more consistent. A few clicks on the sight did the trick. Have now put on the four finger attachment and adjusted tension. Will see how it goes at the range. So far, very happy with it.

 

Is it a thumb button?

 

Yes, it is.

 

I have a Booster Ignite and it worked great for a short while but unfortunately it has now started to fray my D loop every time I use it, I checked it for any burrs but I can't see any so I think its down to the design of the jaws, The upper jaw closes down into a recess and I think the 'corner' of that is what the loop is touching when under tension and although not particularly sharp it is rough enough to fray the string so something to watch out for if you have one.

 

It's a China-made copy of the TRU Ball Blade Pro Flex with a few differences. I would not recommend any release that blatantly infringes on another company's patent.