Kind of interesting, maybe not so useful for the ham bands - certainly cheap enough! Thanks for sharing - good catch
"Decibel Products DB4011 is a band-pass cavity filter designed for the 70–88 MHz frequency range, commonly used in VHF radio systems for improved receiver selectivity or to reduce transmitter noise and spurious radiation.
Key Features:
Frequency Range: 70–88 MHz (FM broadcast band).
Adjustable Selectivity: Achieved via rotating coupling loops, offering insertion loss settings of 0.5 dB, 1.0 dB, or 2.0 dB."