Here is a nice band  pass filter, 250-700 MHz or so,  N (f) , really low loss in the passband. This was made by MFC (Microwave Filter Company & came from an assembly made for the US Army that was a 250-450 BPF consisting of 2 filters on an aluminum plate. Looks like it can handle some power (100 W?) based on construction. With copy of my plot, nice for lab test bench, filter a multiplier chain, etc.  Nice made, originally for military equipment so good quality, Have fun!.