These are factory-direct replacement cores / coils for your SMOK Penn 22 All-In-One device. Rock Bottom Vapes carries all four variants for your vaping pleasure. The SMOK Pen 22 ships with the Dual Core 0.3 ohm coil which features a NiCr heating element. SMOK also offers a 0.25 ohm dual coil version for those looking for a little more vapor production out of their Pen 22. Finally there are also the Strip and Mesh versions of the coil which provide a richer flavor.