Instruction: Generate an answer to the question by utilizing the information contained in the document.

Input:
Question: Is this battery compatible with the Casio Exilim EX-Z77?
Document: This battery has long life (at lease it does in my Casio Exilim EX-Z77 7.2 Digital camera)
The Casio NP-20 is an incredibly small, thin battery that provides great performance for compatible Exilim digital cameras. That is, when it works properly. The problem with this battery is (or can be), that it can suddenly become un-rechargeable for no apparent reason. This is indicated by a flashing red light in the compatible battery charger (Casio BC-11L) when the battery is inserted for recharging.
The rechargeable battery is very compact and works well as a backup battery for my Casio Exilim Digital camera.
casio exilim battery works very well, holds a charge very well and sells at a low price. I'm very satisfied with it.
I ordered this ion battery as a replacement for the one in my husband's new Casio EX-Z75 camera because the one that came with the camera wouldn't charge. The new battery didn't charge either. Based on two phone calls to Casio, we had to go with the unbelievable assumption that both batteries were bad.
I bought this Casio NP- 20 Lithium Ion Rechargeable Battery to replace the one that came with my Casio Exilim camera. The original battery was no longer able to hold a charge. I have been very happy with this battery so far.
The price was right and the battery is a genuine Casio battery not a cheap copy. It has charged correctly from the first charge and is stillworking fine months later. The have been no issues with the battery holding a charge and it fits correctly in my Casio Exilim camera.I am very happy with the price and quality of the battery and give it four stars out of five.
My wife and I own two Casio Exilim cameras that use the NP-20 battery. Within a month, the first battery was bad. Attempting to charge it results in a flashing red light, which is an error condition indicating the battery will not charge. A few weeks later, the second battery was dead too. Casio did send us two replacements for free, and acknowledged having trouble with these particular batteries. After 6 months, one of the replacements died.
I've tried the Duracell DR9611 in my Casio EX-Z4. They work great, BUT, they don't pop out as designed. Only the Casio NP20 will pop out. I don't want to continue to risk damaging my camera by buying the less expensive "replacement" batteries-I'll stick with the original. Thanks!
Haven't actually used the new battery - purchased as a spare. Hope it is better that the original battery supplied with the camera (Exilim). Battery has a sporadic performance history, sometimes failing to recharge. Rating 3 stars based on product history since it has yet to be used. Would rate seller with 5 stars as the product arrived ahead of schedule using the Free Shipping option.
Answer: According to this user's Guide, it is: http://support.casio.com/storage/en/manual/pdf/EN/001/EXZ77_EN.pdf