Rubber for quick break-in time and effective vacuum shut-off. These Universal inflations feature a triangular bore that works well with Jersey cows, 1st-time Heifers, and Standard breeds. Compression happens on three sides of the teats instead of two, making them work for small breed cows (ie. Jersey Cows, Milking Devons, Dexter) Milk multiple cows with a range of teat sizes when your claw has triangular inflations!These inflations fit NuPulse Lightweight or Heavyweight Shells. They can serve as a replacement for NuPulse Super & Short Inflations. Sold in a set of 4.