Nikon SD-800 Quick Recycling Battery Pack for SB-800 AF ...

Don't bother:
Please learn from my mistake. Unfortunately, this item is mislabeled as a "quick recycling battery pack" when it is only an empty battery "container", i.e., a plastic box that houses a single AA cell (that you must generously provide) to increase the recycling capacity of the SB-800 slightly. But Nikon already furnishes such a box with every new SB-800, so unlike true rechargeable battery "packs", this one is neither a "Battery Pack" nor remotely "Quick Recycling". Accordingly, don't consider buying it unless you have lost or damaged the one already included the SB-800.

Surprisingly good for the price:
This is a good inexpensive way to speed up the recycle time. I lost mine shortly after getting my SB-800 and when I replaced it the difference was noticeable. It does not compete with the external battery packs but its less then a 1/10th the price & it fits on the flash. It is a must for the D300 which loves taking rapid shots. Even if you have an external battery pack, this thing packs anywhere and can throw a little extra kick when you do not feel like wearing the external battery pack. Plus you can pick up fresh batteries any where and plug them in to it. I wish replaced it sooner and the price is no more then a pack of batteries.

Don't Buy This!:
Don't be misled by Amazon's "People who bought the SB800 also bought this" link from the SB800. This COMES in the box with the SB800. You don't need to buy it separately! The only reason you would buy this is if the original got broken or lost. After you receive the flash and find you don't need this you will want to send it back. Unfortunately it does not ship from Amazon but another supplier and they will not refund the shipping. It is not their fault that Amazon is recommending you buy something that is already included with the first product you bought but I wasted the $7 S & H from the seller and another $4 to mail it back. Also, this is not really what I think of as a battery pack as it does not come with batteries. You put 1 AA battery in it, connect it to the flash and now you have 5 AA batteries powering your flash instead of four.

Clarification of other reviewer's thoughts:
First of all, it is obvious that this is a replacement for the unit which comes with the SB-800; I'm not sure what the previous reviewer was thinking. Although I would agree that the title is a bit misleading on its function however. The reason for this unit is to get the same voltage when using 1.2V NiMH AA batteries (which typically have much higher mAh ratings). 4 (Alkaline) batteries at the standard 1.5V and 5 batteries at 1.2V both equal 6.0V If you are looking for faster recycling speeds then you want to get the SD-8A Battery Pack or better yet the Quantum Turbo SC Slim (both of which are also available at B & H and Adorama).

A Must get for any Serious Photographer:
This little one extra battery pack WORKS! I am a freelance photographer photographing weddings, football games, and large family events, and with this Quick Recycling Battery pack I get more flashes and a dramatic improvement in the Recycling time. I have had this for over 5months now and I can and have taken over 1,150 Flash Photos on a single Charge, if not more! (using New-Energizer-2500mah) I have seen other photographers with other flash systems (using 4 battery) fail and not get as many flashes as this one will get. Even the 1/1 flash setting has a very quick recycling time. I have Nikon D70 and can take 4 Frames Per Second Flash Shots and the FLASH keeps UP with the Camera. Never before I could do such a thing. I would have to wait after every Flash for it to recharge. Now with the Battery Pack the Recycling time is near Instantaneous and Immediate. No longer will you have to say 'Wait my flash needs to charge, let me get another shot....' Highly Recommended! Pros: Super fast Recycling time in between flashes, A Lot more Flash pops per charge, Not heavy or bulky, Simple and Effective. Cons: most battery charges only have 4 slots, trying to charge 5 batteries at same time is little tricky. (because you always need 2 batteries in a charger To Charge.