The Aspire CF Mod-The stainless steel tube with its elegant carbon fiber can house 1 x 18650 battery with a removeable cap on the bottom. Another great added feature is the overdischarge battery protection. The light that surrounds your firing button will prevent from engaging and will blink orange 15 times. The unique spring connector technology ensures to always provide a strong connection between the battery and atomizer attachment. The stainless steel metal button makes it easy to press and lights around the button for different purposes.