This is a welcome 4-channel RME mic pre, a rarity in a world dominated by 1ch or 2ch preamps. I've confirmed that all 4 channels are working (channel 1 had a slight crackle, which was fixed with ethanol and a cotton swab. I think this kind of age-related maintenance will be necessary in the future). The unit doesn't show much wear and tear, and I think it's in good condition for a used item. The quality is typical of RME, providing a boost while maintaining good resolution!