The third martingale style is the Vegas Style. This is a limited slip design that features a tug that pulls in one direction rather than from the center. Vegas Style collars feature a matching ribbon on the tug. The Vegas Style can be ordered with or without a snap buckle. There is no size adjustment to the Vegas Style collar so if you order a collar without a snap buckle, be sure that it will slide over the widest part of the dog's head. All slip style (limited slip, martingale, etc.) collars should be measured the same way that you would measure for a prong collar. See the video here for how to measure.