This is an empty replacement pod for the TPP-X Pod tank, originally found of the Drag S/X Pro (TPP-X).
The pod snaps onto your existing 510 universal connector using magnets. It has a 2ml capacity and is compatible with all TPP coils.

The semi-hidden button, when pressed, lets you unlock the top part of the tank so you can twist it to access the fill port. Press the semi hidden button and twist left, to unlock. Lift-up the rubber tab to fill-up the tank, then close the tab and twist right to close the tank again. (See pictures gallery).