I see you asked about the different color tops in another question today and I answered that there. The more GH you use, the higher the serum number would be, so they are posting syrum numbers to provide some data on how strong the GH is. So assume that a higher number could mean better GH. As for the needle, you want to use an insulin needle to inject. I use a 1/2cc, 1/2 inch, 29g insulin syringe. I prefer to do my GH shots via IM, into a tricep or delt,  but it can also be taken Sub Q