The 3TNF-3000/4000-N/N from K&L Microwave is a Tunable Filter with Frequency 3 to 4 GHz, Bandwidth 10 MHz, Insertion Loss 0.5 dB, Supply Voltage 24 V. Tags: Benchtop, Mechanically Controlled, Digitally Controlled. More details for 3TNF-3000/4000-N/N can be seen below.