“Thanks to Allivet for offering these pens as single/solo purchases. Lantus is an expensive product, and most of us with small pets would not be able to afford a whole vial of something we’d have to throw out because it expired before we could finish it. But Allivet has solved the problem. To make things better, they contact your vet, AND let you know that, so you can contact your vet if needed. Great customer service. To top it off, they ship at lightning speed. I am a happy repeat customer, and highly recommend Allivet to other pet parents. (No, I have not been paid or otherwise compensated for writing this review. These people rock it.)”