Shure PS23US Energy-Efficient External Switching Mode 12V DC Power Supply Energy-efficient external switching mode 12V DC power supply For use with BLX4, BLX88, BLX4R, GLXD6, UABiasT, PG4, PGX4, PGXD4, SLX4, SLX4L, P2T, FP33 Legendary Shure quality to withstand the rigors of everyday use