The Prism-S is the next generation tank and coil system. Focused on pure flavor and throat hit, this MTL tank provides an exceptional experience in how it vaporizes e-liquid.The coils for T20S tank are  Prism 0.8 ohm or 1.5 ohm and you have 1 spare in the Box Suitable for Most devices , an all round very affordable Tank for your Mod/ Battery