The API Model 500VPR is powered externally by a tri-polar power supply (included) and is designed to accept API standard format 5.25″ X 1.5″ modules. The 500VPR is internally wired for PIN 2 hot, and comes with the API L200PS. The input/output jacks are both XLRs. The 500VPR can hold up to ten API modules. [...]