Great bottles but  people should get up into the future.  These have rubber bulbs and essential oils melt them like they are some sort of drink mix in warm water after awhile.  It should be acknowledged that for water based liquids or thick oils, these may be ok, but you are going to have to get monprene or some other polymer if you want something to withstand the dissolving power of some essential oils after time.  Noting liek essential oils contaminated with bits of degenerating rubber and the scent of rubber dissolved in it.