Heart Slide buckle (with no prong.) The buckle is 1 3/8" high and can take as wide as 3/4" fabric through it. There is simply a bar in the center to slide over the belt of your choice.
I embellished Bat Mitzvah invitations with this heart buckle. Rave reviews on the quality of the rhinestones the guests. They were able to wear the buckle after they received the invite.
I've been embellishing flip flops with these buckles, and several of the other styles, for over 3 years and never had a problem. Customer service is excellent also - they respond very quickly and let you know if there's any issue with your order within hours. Great company!!