Just thought I'd add here, in case some don't know it, that BLU brand cartos work on 510 devices. The connection is the same, and the carto is a bit smaller in length and diameter.
They can be found at Walgreens, among other places, in a pricey 5 for $15 small box. I have found the classic tobacco flavor (custom by Johnson Creek) to be quite good, but I've also found the cartos to be inconsistent in fill and longevity. They can be topped off easily, and make for a pretty good emergency purchase.
They can be found at Walgreens, among other places, in a pricey 5 for $15 small box. I have found the classic tobacco flavor (custom by Johnson Creek) to be quite good, but I've also found the cartos to be inconsistent in fill and longevity. They can be topped off easily, and make for a pretty good emergency purchase.