Compatible with P3RA (PSM300), P9RA+ (PSM900) and P10R+ (PSM1000) Receivers, ULX-D, QLX-D and Axient Digital (AD) Series Transmitters and All Associated Docking, Networked and Rack Charging Accessories. Functionally, this battery (SB900B) is a direct replacement for the SB900A and works with all of the same products and charging devices. What are the differences between the SB900A and SB900B batteries? The only difference is a slight change in battery runtime, reflected here: AD (2mW/10mW) = 9 hours (SB900A) to 8:30 hours (SB900B), ULXD (1mW/10mW) = 9 hours (SB900A) to 8:30 hours (SB900B), QLXD (1mW/10mW) = 9:30 hours (SB900A) to 8:55 hours (SB900B). All runtimes reflect UHF TV band systems. Battery life may vary with frequency band and output power.