The Shure PS20US power supply was discontinued by Shure and replaced with a newer, 100% compatible, energy-efficient version. The PS24US is now the recommended replacement power supply for failed PS20, PS21 and PS23 power supplies for Shure 200M, FP22, FP24, FP33 mixers, Shure P4M and P4T PSM Receivers, and the SLX4, T3, T4V, T4G, T4N, T88, LX88 Wireless Receivers and other T, LX, UT, PGX, SLX, and PSM wireless equipment.