I am glad that Max is doing so much better after his stay with the vet.

You should only use a needle ONCE. More than once it will develop little burrs and loose it's sharpness causing pain and discomfort when they are injected under the skin.

BTW, you know that you can buy all the supplies online including the fluids and necessary equipment. I like my vet but they are mucho$$$$, so it was cheaper to order everyone from the Internet.