Notch filters are designed to knock out specific bands of radio interference. They have significantly lower loss than high pass, low pass, or band pass filters and often have higher than 20db choking capability.
The 433/1.3 filter is used on your UHF radio when flying on 1.3GHz video.
Specifications:
Passband: 380-500MHz
Reject band: 1220-1360MHz
Filter strength: 24db