The Letter Hey(or Heh) is basically a Dalet which has an upside down Yud at the lower left hand corner, at an equal distance away from the roof as from the leg. The heel that was found on the roof of the Dalet isn't necessary on a Hey, as even if the body looked like a Reish it would be kosher, but most Sofrim put a heel on top anyways. There should be one Tag at the left end of the roof. (This Tag should not be on the very end of the left side, nor be made too large, because it can be a problem.)Great care must be taken so that the left leg does not touch the roof of the Hey. If it does touch, even with an amount as thin as a hair, it would be invalid.