The Square E-Head Electronic Hookah Bowl is an amazing and innovative addition to your hookah setup. Eventually the heating coil of your E-Head will wear out, and will need to be replaced. If you need an extra coil without replacing the entire clearomizer tank, these are individual coils. Replacing the coils on the E-Head Bowl is incredibly simple. Just screw off the top of the flavor tank, pop out the old coil, and push in the new one (it snaps right in).