Kangertech GEM Cartidges are for use with the Kangertech GEM Refillable Pod System. Each pod holds 2mL of liquid and feature a ceramic 1.2 Ohm coil. The pods have an easy and clean bottom fill design. Its as easy as popping the plug and filling with your favorite flavor! Convenience and portability was the target when they were designing this product and they hit the mark head on!