Luer Slip means that the needle slides onto the syringe instead of screwing or twisting on.
These syringes from Monoject are a good stable product. I have found that if I am injecting penicillin which is thick, it is better for me to use a luer lock type. But for giving vaccines, these are great. The needles are SHARP and don't have snags that the cheaper ones have. The slip type is also good for an eye dropper type use without the needle of course.
This is the only Jeffers product I've ever had a problem with (3ml 20g), but the needles are constantly separating from the syringes during injection of very viscous meds. The 20g is properly sized, but the plastic hubs just won't stay attached, and won't firmly attach even after the med draw. The few times the injection was actually delivered, the needle remained in the animal when the syringe was pulled. Material quality appears excellent, but fit is bad.
"consider the gauge"
Not being a frequent vaccine giver, I used William?ÇÖs advice and purchased the 22 gauge. If you are using the needles on small animals like cats, I recommend getting the 25s. The needle is smaller, so it probably depends on the application. I found that for vaccinating outdoor and battle-hardened neighborhood strays, the 22s were almost impossible to insert subcutaneously. My vet confirmed that old tom cats have skin like leather. So, I?ÇÖd recommend at least considering the littler needle or getting a few of each if you are working with both spoiled inside felines and street punk toms. The amount of time it took to inject with the smaller needle was insignificant.
these are very good quality hospital grade syringes with sharp needles. Don't get the 25 ga. They are just too tiny to use routinely. Start with the 22 ga. X 3/4 inch which will cover all situations. Occasionally a syringe needle will pop off the syringe during the injection because they are not locked on....doesn't happen often so no star deducted.