Image 1 of 1 Syringes from $5.00 1 mL 5/16 Inch 31 Gauge insulin syringes for self-administering peptide injections. Quantity: Select Quantity 20 50 100 Quantity: Add to Cart Added! 1 mL 5/16 Inch 31 Gauge insulin syringes for self-administering peptide injections.