Boss Cafe Base Original Milk Frother Set of 6 This was a bonus item from a product purchase several years ago. It was stored unopened, but I opened it to check the operation for this listing. When I inserted batteries and checked the operation for just a few seconds, all of them worked at that time. However, there's a possibility that some may not work later on... Please understand this before purchasing. The packaging has wrinkles, scratches, dirt, etc. Requires 2 AA alkaline batteries. These are not included, so please prepare them separately. This is a home-stored item under amateur management, so please refrain from purchasing if you are sensitive, particular, or seeking perfection. We ask for your understanding and agreement before purchasing. Please check my profile before buying.