Well it’s labeled the largest, not the most powerful. Those are different categories 
Coincidentally, this reminds me of a story someone’s dad told me. When he was young he and his friends would steal the reusable fire extinguishers that are filled with pressurized water, fill them halfway with water and then pump them with air from a compressor until it went just barely above the NOT SAFE level. Then they’d drive around town blasting unsuspecting victims from the car.
