Best Class A fire extinguisher

I have the Kidde fire extinguishers with 3.2 lbs of 'stuff' and the dial showing if it is still good. While pulling into a gas station towing my boat with my Class B I saw a car pull into the lot, not near the pumps, with smoke coming our from the engine. The guy and girl hopped out and opened the hood and flames were building. I got one of my extinguishers and ran over and put out the fire using the whole thing. I told him to go talk to the station attendants in case it restarted as they may have bigger extinguishers.

I have 2 extinguishers in my small RV, 1 on the boat and i in my kitchen. I've also given them as gifts to my siblings.