The Kanger SSOCC coils are the updated version of the Kanger OCC coils and are manufactured with stainless steel casing, hence the acronym, SSOCC. The wire used in these coils is made from Nichrome. They also differ from the OCC coils in that they are cylindrical in shape and therefore take up less space/volume in the tank they are being used in, as opposed to the cuboid shaped OCC coils. The SSOCC coils ship with the Nebox, Topbox Kit and Subvod Mega at the moment, with them likely to be introduced across all of Kangers products at some point soon, in effect, replacing the OCC Coils. The SSOCC coils are backward compatible and will work in any tank that currently takes the OCC Coils. Please Note: The 0.5 Ohm SSOCC coils are the updated stainless steel coils and feature 2 wicking holes instead of 4. They have the same compatibility as other SSOCC coils.