The SMOK NOVO 4 Cartridge is an empty pod unit without a coil, when embeddings the coil into the pod, the added silicone ring on the lower part of the coil would fill the gap, effectively stemming the liquid leaking from the pod that outcomes in a chaotic vaping experience or filthy hand. The SMOK Novo 4 Cartridge is compatible with LP1 Coils, and you need to purchase the coils independently.