Check the year (embossed near the bottom.) I took an Amerex in to get serviced (recharged) and was told they couldn't work on it as it was too old. 1984 was mentioned as a year cut-off.
I prefer water and cold fire refillable extinguishers. Handles most garage issues. Buy a NEW or freshly serviced dry chemical as they do expire due to settling even though they say they are good.
Here's why.. If you ever have to pull the pin and squeeze the handle on those for a small fire, you are going to hate life when it comes to cleaning up stuff. That powder is extremely corrosive (rusted matco sockets in 24 hours once for me)
I'd rather have one or two good, halon extinguishers, than 4-5 old outdated ABC extinguishers.