Have you heard of Green World products? I have two the G300 and the G400. I started with KR808s because I liked the two piece design. but after using them a while I was spending so much time cleaning them and I started throwing them away because they tasted BURNT. I thought the Green World products were too expensive, until I added up what I spent on the KR808s. I have 10 G400 carts and 10 G300 carts I have been using them for 3 months and have only used 5 of each. The G400s open easily and I clean and refill them. A refill of the G400 lasts more than a day. The G300s I drip 3-5 drops in the battery end and they work well.