I believe the coils are .25 SS in the crown tank. Originally bought a vtc mini which I loved but was a little underpowered for the crown tank and when I borrowed a friend's cuboid, showed me what it was really capable of @ 90-100w and temp of 500f. I should have bought the cuboid but after reading up I thought the ipv5 was a newer and better product. Just missing the ease with joyetech products seem to have while adjusting or maybe it's just that it's popular and able to find through Google step by step instructions which I can't seem to find for the ipv5