4 in 1 Filter: Compatible with popular receivers, radios, SDRs, and Malachite devices. This product includes four band-pass filters, divided into four frequency bands. The P1 filter covers 0.5-1.5MHz, ideal for medium-wave radio reception. The P2 filter covers 4.5-12MHz, suitable for shortwave and lower frequency bands, including the 40-meter amateur band. The P3 filter covers 12-30MHz, supporting high-frequency shortwave bands and the 20-meter, 15-meter, and 10-meter amateur bands. The P4 filter is designed for FM broadcast frequencies, 88-108MHz. These filters can be used with a one-to-four active splitter to provide pre-filtering for SDRs, radios, and receivers. Enhances performance by adding pre-filter functionality to Malachite SDR devices, reducing interference from strong signals in medium-wave, shortwave, and FM broadcast bands. The filters operate in the following frequency ranges: 0.5-1.5MHz, 4.5-12MHz, 12-30MHz, and 88-108MHz, and can be used with a 1-to-4 splitter for simultaneous multi-band reception. Material: Aluminum alloy. Color: Black. Package includes: 1 x Passive Filter, 1 x Mounting foot pad. Note: Lighting and display differences may cause slight color variations. Measurement tolerance: +/- 1-3cm.