The K1 consists of an Aspire 900mah battery and a K1 Tank and is a newer tank which uses the Aspire “BVC” (Bottom Vertical Coil) technology. This new technology is designed to last longer while still giving users the best performance. The Aspire CF battery is a well performing power system and features stainless steel endpoints, a metal button, a carbon fiber coated tube and 6 safety holes on the bottom cover for ventilation.