Vaporesso SKRR Replacement Coil Heads are designed for SKRR Sub Ohm Tank. It has three types optional: QF Strips 0.15ohm coil or QF Meshed 0.2ohm coil. QF Meshed coil creates intimate contact with the organic wick for rapid and even heating. QF Strips provides rapid, even heating. QF Strips are the longest-lasting. Each of them will bring you pure flavor and different vaping experience.