With gravity feeders (where the milk level is higher than the teat) two issues arise.  First preventing leakage through the teat, second is whilst preventing leakage, still enabling the calf to suckle freely.  The Big Softy achieves both of these.  (See also Peach Teats, pull through and screw in which also achieve this but incorporate a non-return valve.)

• design does not leak even after substantial use
• Teat tip opens freely as soon as calf begins to suckle
• Fits all feeders with standard 22mm (+/- 1mm) teat holes including Milk Bar and 50 teat Daisy Feeder
• Equally suitable for bottle feeding