Came in to purchase a battery for my cartridge, and the lone battery they carry was defective upon opening. It has been charging for nearly 8 hours, and while it will turn on, I get a blinking red ring whenever I try to use it or adjust the voltage. No functionality whatsoever. Would recommend the store based on friendly staff, but strongly recommend you not buy their branded battery. Bought it before traveling hundreds of miles away and I still can't medicate as I need.