Abstract: An improvement in milking inflations having a teat-receiving collar wherein the inner periphery of the collar is of generally uniform thickness and the projection of the periphery onto a plane passed perpendicularly to the major axis of the body portion of the inflation has a generally circular configuration with a perimeter of finite length, i.e., the projection is substantially circular. The inner periphery of the collar is formed of a series of contiguous wave forms. If the aforementioned plane is passed through the periphery of the collar, the contiguous wave forms may be considered as representing periodic oscillations above and below the aforementioned plane, the true length of the inner periphery along the wave forms exceeding the length of the projected perimeter.