In the world of tattoo machine customization, all coils are not created equal. I have found eikon coils to be solid and consistent. I prefer the 8 wrap 1″ coils. Eikon does not ship their coils with a capacitor and recommends that the coil system should remain separate from the cap due to the fact that a quick customization of the machine can occur by changing out the coils and caps independently via pre-soldered lugs on each respective part of the machine. The coils are very symmetrically rounded and the wire is typical gauge. The coils come with a plastic piece of tape or sticker on the outside that acts as the coil’s cover. These covers are easily removed for customization of the coil cover (ie 3M shrink wrap). The coils are a good width and the cores are consistently tapped and threaded. On top of the coil is a small sticker that greatly improves sound of the running machine when the armature bar strikes the front coil. It appears that the coils are the same height in matched pairs, where some coil fabricators will actually use a shorter height core for the rear to compensate for the suggested gap on the rear coil and stressed armature bar (ie the arm bar is held down by its nipple so that it lays flush on the front coil).
Quality coils at a very good price. Eikon produces a lot of good gear and the coils are right up there. I recommend these coils.