Sorry Max Power information is not available yet.
I have asked Ryszard about the max. power , he answered:
The filter cooperated with an amplifier of about 50W.
Staszek SP6GWB made tests with 150W power
The maximum power is limited by the SMA connector ..."
This is a very good BPF with low attenuation and high max power.
Now I have to tune it to 2.4 GHz. We will see...