Replacement coils for e-cig tanks and clearomisers from all the top brands.  Aspire, Smok, Innokin, Geek Vape, Voopoo, Freemax, Horizontech and many more.

As a general rule the lower the resistance of the coil, the higher the output.  For example a 1.8ohm coil would be much more gentle than a 0.15ohm coil.