I saw one video with 2 SS cables through the 2 holes, then with a cotton bed on top, with micro coils and cotton going from the bed through the coil. It has set screws on the side to hold the cable in place which is used just for wicking. It also looked like it had set screws for the fill holes, so you could open them fill then close them off, but it was in German making it a bit confusing to follow. Another feature that looked kewl was you screw the top cap down till the air holes lined up and then there's a lock ring below it, which you tighten to lock the cap in place. It is basically designed to accept many different types of builds dual or single coil. Plus it's like a supertanker, 27mm dia, 6ml tank capacity. Looks interesting for a top loader, may have to check it out.