PetTest U-40 Syringes, 31 Gauge x 1/2CC with 5/16-in needle are the WORLD'S THINNEST U-40 insulin syringes.  This helps make injection more comfortable for your furry family member compared to thicker 29-gauge U-40 needles from all other U-40 syringe makers.  The length of the 5/16” needle also helps reduce the risk of a painful injection to your pet’s muscle or those peky "through-shots".. These syringes are specifically designed to be used with all U-40 insulins. Both sizes, the 0.3-cc and 0.5-cc have easy-to-read ½ unit marking for accurate dosing every time. The needles are extra sharp and lubricated and have a tri-bevel tip for added comfort, while the extra-wide finger grips allow for unmatched control. These syringes come with protective needle and plunger caps and come 100 per box (in ten 10-paks).