The Ccell-GD coils have been developed especially for the Guardian tank. These coils deliver maximum flavour, with no dry hits, no burnt cotton, and a long life.
I have found the flavour to be excellent from these coils with no noticeable 'break-in' period.
Changing the coil is very simple since it is not screwed in place – it just lifts out. However, there is a notch on the side of the coil that mates with a matching tongue in the tank; you need to make sure these align as you push the new coil in place. This feature stops the coil turning when the top cap and mouthpiece fitting are reinstalled.