Since we have a very large 25 MHz split on 900 MHz is faily easy to get in excess of 100 db notches on each half of the four can duplexer. Insertion losses are around 1 db as well. This means they can easily handle 100 + watts. A single low loss transmitt band pass filter (0.18 db loss) is added to the transmitter port of the duplexer to help attenuate out of band signals from entering the power amplifier where the dual stage isolator ceases to operate.
Insertion loss plot, transmit section
Insertion loss plot, receiver section