Sissy was chipped at the local animal shelter just a few months ago. The chip is a little longer than a grain of rice, about the width of a cooked grain of rice, and is dark in color. I know this cause the first chip implanted fell out later that day
But the 2nd one was implanted with no problem. It goes in between the shoulder blades and I can feel where Sissy's is.
Sissy is 4 lbs in a body that looks much smaller and she did just fine with the chipping without anesthesia. She actually yelped less than when she received her vaccines. I chipped her because she doesn't regularly wear identification. I hope I never have to use it. The one thing that it does protect you is if someones steals your baby and you find her, you can verify she is yours by the microchip.