I really like this mod. Negatives first, the button is a little 'mushy' when firing and I would have preferred 25mm at the 510. Positives, the button lock is great, the mod feels great in the hand, performance is excellent, button fires perfectly wherever it's pressed, fit and finish is top notch and it looks really nice imo. Totally worth it at China prices for anyone who wants a 21700 mech.