Now you can match your favorite decora light switch with screwless volume control. All speakers have an impedance rating, typically 8-ohm for a pair of home speakers. To operate in the safest mode, most standard amplifiers and basic two-channel receivers are rated for an 8-ohm incoming load. To operate safely and consistently, the amp needs to see an 8-ohm load, and that’s where speaker selectors and impedance-matching volume controls come into play.