Just to add confusion, I've referred to the "correct" Hawkins as the "heart-shaped openings" and the other as the Hawkins "Depression" pad. The "correct" pad for a mid-teens smallbore Sterlingworth would be a Jostom Anti-Flinch with six slots. In addition to the Silvers and the B.F. Goodrich pads, Jostam had a similar pad called the "Air Cushion". On higher grade Ansley H. Fox doubles that were "supposed" to have a Silvers pad, I've often found the Jostam Air-Cushion.