It's an ego cartomizer.
Inside you have the usual poly fiber on top of your heat coil. The heat coil is sitting on a plastic base, which is a bit iffy as it has a tendency of melting, if you keep your finger on the switch for too long.
Make sure not to run this carto dry or it will make for a really bad taste that you will not be able to get rid off. These cartos are difficult to clean because you have no physical access to the inside.
Be careful with putting them into your pocket. Once the connector comes loose (it doesn't take much force) the carto will leak and you will not be able to seat the connector back in place without some surgical instruments (I'm dead serious!!!), which makes it difficult to unscrew the carto from the battery.
Other than that these cartos are great and I have a stash myself in black, white, red and pink <grins>. If you run out, try the echo cartomizers next time around (price is about the same).