This spring is very, very powerful. So powerful, in fact, that it sheared the plastic connecting the plunger to he plunger head when I accidentally dry fired it. However, my knockout was a TKO with the air restrictor removed, so your mileage may vary. The few shots I did get through it before it broke were amazing though.
Fast shipping, would buy from OOD again.
Out of darts did a great job packing and shipping both my orders..... but were here to talk spring power.
The installation was easy and quick (about 3m total) and now the blaster fires quicker and more accurately with a cool/scary new sound.
Please remember that this is not an upgrade for younger players and IMO you should always test a blaster on yourself before firing at others. (too strong for kids or pets) that being said I totally recommend this 25kg spring it's a super fun and easy mod.