Syringe
1) Desired brand
2) Gauge
3) Volume
4) Needle Length
Brands of needles vary depending on what pharmacy you go to, however, most pharmacies will stock common brandssuch as BD, or Terumo.
As for the gauge of a needle, most people will prefer a 27 to 31 gauge needle. The larger the gauge number, the finer the needle. Anything larger than a 27G is not desirable for what you all would be using needles for.
The volume represents how much liquid the syringe can hold. 1cc = 1ml = 100 units. There are 0.3 mL, 0.5 ml, and 1 ml volumes which are standard at all pharmacies. For drug use, unless you know that you don't need a large volume, you will probably want 1 ml.
The needle length options will vary depending on the gauge, but the common ones are 5/16" (also known as short tips), and 1/2" (also known as long tips). You will need to determine which length is more desirable for you, often IV drug users will have their heart set on one or the other. There are longer and shorter needles as well, but are less often used overall.
