My horse has a silicon allergy! I get mine from AirTight. all my vets carry them now too. I carry them in my trailer as well. Got pulled for USEF testing at a show and initially they insisted that they had to use their needles. I said no and made them get ahold of someone at USEF on a Sunday. USEF initially said I had to let them use their needles if I wanted to show. I conferenced in my wonderful vet who confirmed my horse's allergy and after 30 minutes USEF agreed to let the on site vets use my needle. I now carry a notarized letter from my vet everywhere we go.