Three in one is the main motto here. The idea is to avoid having to plug and unplug different guitars in to one amp. As you may know, this is not done quickly and easily without causing considerable noise. With the TRINITY - box you can selectively switch three instruments on to one output. In addition each input can be boosted up to +12dB by an individual stepless pot. This helps to balance out differences in level between the instruments without having to change the amps settings.