The media could not be loaded. This is a real game changer for nerf, this rechargeable pack reduced weight by nearly 3 pounds and significantly increased the rate of fire on the fully automatic Khaos (see video). Balls fired increased from 2.5 - 3 shots per second to almost 5 per second. Nerf actually advertises increased firepower in their ads, but this exceeded my expectations. . I know it's hard to believe it could make such a difference in a stock non-modified gun.

Don't just take my work for it, watch the side by side video I made to show the improvement. Hopefully this review, along with the side by side slow motion video will answer any questions you have and send you out to the store before the next fully auto gun hits the market. Word is it will have a hopper that holds over 100 nerf balls. I hoped this help.

If you have the Nerf Rival Khaos, this is an essential counterpart for the blaster.
Regular users of the Rival Khaos should notice that their blasters performance slowly begins to decrease after a while. This is because constant use easily wears out the prescribed D volt batteries. This predicament forces users of this blaster to change batteris every month or so. You do not want that. 6 D batteries cost around 17.00 $, so after a year, you've payed more than triple the amount of the already expensive but amazing Rival Khaos.

Fret not! There is an alternative! Behold, the Nerf Rival Khaos Rechargeable Battery Pack, a.k.a. a very smart choice. If you buy this, you will save so much money on batteries for your Khaos blaster.

And that's not all! This battery pack also makes your Nerf Rival Khaos astonishingly lighter than with standard D Batteries.

So yes, you should buy this, but only if you want to save hundreds of dollars and lower the weight of a very heavy blaster.

(Update)-This battery pack is also compatible with the new Rival Nemesis

This Nerf Rival battery upgrade is decent, although it is still inferior to stronger voltage modifications (namely, LiPo or IMR batteries). This rechargeable battery pack will replace the need for a battery tray and noticeably increase the performance of your Rival motorized blaster. It is labeled as a 7.2v NiMH 1500 mAH Rechargable battery and comes with a wall-charge cable. There is a small red light on the adaptor plug that stays on while charging and it will blink when it is fully charged. Once installed, the rev-up time increased my Khaos by 3/4 of a second, and it added approximately 13 Feet Per Second (FPS) as well. It also fits in my Nemesis, and Hera (so far; at the time of this review, 11-8-2017). It will also increase the Rival Rounds Per Second (RRPS) another 2 balls (approx 5 RRPS instead of 3 RRPS). This battery will also be a lot lighter than the store- bought Alkalines (i.e. x6 Duracell/Energizer 1.5v D or C batteries) and should save you close to 3 lbs., which is kind of a big deal when running around with an already large blaster in your hands. It is suggested that you wait for the price to drop though, since I purchased my battery pack at close to the entry price (mines was an Amazon Warehouse Deal; used) of $30.00 (It is currently $24). Perhaps the best part about this rechargeable battery pack is the fact this will end up paying for itself because it is rechargeable. You know? So you do not have to keep buying (and wasting) lots of large and costly D (or C)- sized batteries.

This thing powers the nerf gun to the lecture level. The rate of fire must have doubled and the velocity is significantly different than off the shelf batteries.

This battery is NiMH, which is a slight disappointment considering LiPo and LiFe batteries are common these days. NiMH is still decent technology and if you take care of it should last quite a while. It is 7.2 volts and intended to replace the 6 D batteries in your Nerf blaster. NiMH cells are 1.2 volts per cell and Alkaline batteries are 1.5 volts per cell, so by using this instead of D's you're actually losing 1.8 volts. They could have made a 7 cell NiMH battery which would have been 8.4 volts... but they didn't. Compared to the D batteries, I really didn't notice a difference in rate of fire, accuracy or distance. D batteries are ridiculously expensive and heavy, so this is an upgrade in every sense... less weight, less expense long term. No regrets on this purchase, but I'm pulling one star for Nerf using old technology and not having the forethought to add another cell to more accurately replicate the voltage of the original battery configuration. Keep in mind, 4 stars is great... a 3 cell LiPo or some more modern setup would be fantastic.
TLDR version: Get it!