The Aegis Boost Replacement Coils By Geekvape are designed for MTL and DTL vaping experiences. The two Kanthal Mesh coils are a GV Boost 0.4ohm used for DTL vaping 25-33W recommended range and a GV Boost 0.6ohm coil for MTL vaping 15-25W recommended range. The 0.2 ohm offers better sub ohm DTL vaping.