The sweet heart pins as one posted are in many cases no longer made by the one jewler, just regular size Badges.
Laviliering or wearing of the letters show that this is a members girl friend and is under the protection of said fraternity. This I assume goes back to the day of heraldy and protecting a lady from brigands and usurpers!
Pinning as it was known has I think long paqst by the way side. One has to be very serious about the lady as Badges cost a lot of more money today than they did then! Along with the fact that many Fraternity members today do not even buy Badges or wear letters. How said that is!