I've only had my 808 for a few weeks now and I'm new to cartomizers, so I'm hoping you'll help me out. When I ordered my 808, it included 7 black cartomizers. I also ordered a pile of supercheap ugly brown ones, all prefilled that don't perform nearly as well as the black. I've now started refilling some of them. I prefer refilling from the top, and have found the brown ones have a rubber gasket inside and the black ones don't. Why is that and do I need that gasket? I've tried leaving the gasket out and it doesn't seem to make any difference, but am I shortening the lifespan? I'm not expecting a very long lifespan anyway, as they were 2.99/5, but I'm curious about the gasket.