I always like to have a spare battery for everything I own that has a battery that can be replaced. One of the batteries for my Pentax Optio 550 will no longer hold a charge so went to major camera store and they didn't have one. Tried a well known battery chain that supplies batteries for everything you own. They have a number of stores in the Salt Lake City metro area. None of them had a battery stating they were no longer made. Yes, my camera is about 20 years old but still works perfectly. Searching the internet I did locate one for $56.00 but then while scouring Amazon I found the battery for $11.99. It wasn't eligible for Amazon Prime two day delivery but did have free delivery for 8-10 days. I received it within three days after placing the order. In addition it is rated higher than the original Pentax battery

Rated at 3.7V and 1900mAh for a longer run time than the Pentax original (My original Pentax battery was rated 1800mAh)
It fits the Pentax charger and comes with 3-year manufacturer warranty

Finding batteries for my camera had been hard until I found these. They arrived in a reasonable time and fit perfectly into the charger. Now all charged up and ready to keep me going when I'm shooting.

I have used them for 2 months & they are as good as OEM.

Works good but took a long time to arrive. Therefore lost a point in my rating.