Some modern-day head units monitor their speaker outputs for a low impedance load. If not seen, they selectively turn channels off. When using such head unit's speaker outputs with the high level (high impedance) inputs of a bit product, channels can be caused to switch off. The USS4 completely cures this issue accepting up to four channels. Furthermore, this hideaway box allows for a turn on delay of up to 8 seconds to be added to avoid annoying "bumps and bangs" on power up.