Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A must if you use CR-V3 batteries

Pentax K100D can use 4 AA batterie, rechargeable or not, ot use 2 CR-V3 batteries of the non rechargeable type. The CR-V3 are the longest lasting batteries by far, but at my local supplier are about $20 for a 2 pack. In this case using the K-AC1OU Adapter makes "cents" whenever you are in a studio-like situation where you can shoot while your camera is plugged into the wall outlet. (Also, when downloading photos directly in your computer). The cord is pretty long and you can use an extension cord.In any event and although I use now rechargeable batteries, a sure backup power to have on hand.