This is for one Genuine Aspire ET-S Tank which has an ego thread fitting.  The ET-S BVC is an upgrade version of ET BVC, it has an exterior metal sleeve surrounding the tank with two small pyrex glass windows that allow you to see how much liquid is left in the tank at all times.

Contents:
1 x Aspire ET-S BVC Clearomizer
1 x 1.8 ohm coil (1 preinstalled in clearomizer)

Features?
Bottom Dual Coil Technology
2.0 ml Capacity
Dual windows liquid level
Big Vapour production
eGo Compatible
Filled from the bottom: Unscrew the base and fill tank while avoiding the metal airflow tube in the center.

Coils also available in this listing.