The Smok Novo 4 Replacement LP1 Coils is specially designed for leak-proof vaping. Each coil in this series uses 3 silicone rings to provide tightness. When inserting the coil into the Smok Novo 4 Pod,the added silicone ring on the bottom of the coil would fill the gap,effectively stemming the liquid leaking from the pod that results in a messy vaping experience or dirty hand.