Well known lamb and kid feeding teat, which can be used in a ´calfeteria´ type feeder.
The teat can be fitted through a 14mm hole and will take 11mm o.d. calfeteria-type delivery tubing in the back.
Or it can be stretched over a ´pop´ bottle as a bottle feeder (but needs an air-inlet in this configuration).
Cross-cut or round-hole tip. Hole teat is softer.
Round hole = pink
Cross-cut = black