One particular type of step-through frame is called a mixte. In a mixte frame, the top tube of the traditional diamond frame is replaced with a pair of smaller tubes ("lateral tubes", or "lats") running from the top of the head tube all the way back to the rear axle, connecting at the seat tube on the way. The normal seat stays and chain stays are retained. This provides the lower standover height of a step-through frame bicycle with a strong diamond-frame geometry.