[B4Ranch]

I suspect it's not so much the needle that hurts anyway, but rather the volume of fliud injected.

You are correct. The longer needles are able to be iserted further into our tissue. IF the needle is slowly withdrawn as the fluid is injected there is less tissue separation and therefore less pain results. If a person is very sensitive to pain, the placement of the needle into larger muscles with fewer nerves stems can also be a pain reducing factor.

[Chemist_Geek]

Yeah, what kind of flow rate is one going to expect from this 2/3rds of a 30 gauge micro-needle? I'd only expect it to be useful for low-volume sub-q injections...