The D-fend SA300 keep your system safe, but your venue and audience as well. With D-fend there are no more worries about blown speakers, HF drivers or crossovers. Or even worse: fire caused by excessive heat. The user simply sets the thresholds and D-fend monitors and limits the amount of input power it passes through to the loudspeaker. It’s USB compatible, and can be programmed to your specifications from a desktop or laptop. Just set it and forget it. Protect your products, venue, customers, and your reputation with the first passive speaker protection system that is virtually indestructible.