Both OCC (Organic Cotton Coil) and SSOCC (Stainless Steel OCC) apply Japanese Organic Cotton. With pure organic cotton, these coils can provide amazing flavor and vapor with your MODs / batteries. Subtank /TOPTANK /UD Zephyrus are hot products with these coils. They're the most popular ones. Except prebuilt coils, you can DIY OCC coils.