The Vapefly Optima Replacement Pod Cartridge is designed for Vapefly Optima Kit. The Vapefly Optima Cartridge types are Normal cartridge, RDTA cartridge and RMC (rebuildable mesh coil) cartridge for different needs. The Normal Cartridge is best for regular FreeCore meshed coil. The RDTA Cartridge is perfectly for both DIY mesh and pre-made coils building. The RMC Cartridge is compatible with the latest RMC rebuildable meshed coil. 1 piece each pack.