4 Balanced Stereo Audio Signal Input Selection Relay Module This item has passed assembly, electrical test. You can connect 4 balanced stereo signal input/balance stereo output. ry12w-K Signal Relay (Contact Material: Gold Overlay Silver - Palladium) LED indicator for each relay channel Bulk terminal block, easy connect wire. FR-4 Fiberglass PCB Operating Voltage: 8.5 - 15 5VDC recommend 12VDC Working current: 15mAh (at 12VDC) Rotary Switch Wire Length 300mm (11" 8) Size:115mm(L) x 50mm(W) x 16mm(H) (4) 53" x 1" x 97" 0 63")