VocoPro UHR4 Must be used with existing compatible systems. Compatible with UHF-5800, UHF-8800, PA-MAN, PA-PRO 900. Comes with 4 microphones and 2 charging stations. 2 frequency sets available:. UHR-3: M, N, O, P. UHR-4: Q, R, S, T. Utilizes 3.7V, 800 mAh Li-Ion batteries FCC license may be required. UHR 4 Rechargeable UHF Wireless Microphones with Chargers Upgrade Kit Item # 692868 . Not a stand-alone unit, must be used. in combination with a compatible unit