Small 5/16" Tip - Cockatiels, Parakeets, Canaries, Finches And Other Softbill Birdsmedium 7/16" Tip - Conures African Greys, Quakers, Senegals, Amazons, African Greys And Other Hookbill Birds Large 5/8" Nozzle - Large Parrots, African Greys, Macaws, Cockatoos Etc (good For Dogs And Puppies Too)extend The Use Of Your Bottles With Replacement Parts.quality Stainless Steel Nozzlesafe Rubber Stopper Three Sizes Available For All Gb-16 Oz Lixit Bottles.