... distance without block. wireless cameras system, 2.4GHz wireless camera system, wireless camera kitsName: 2.4GHz Wireless IR Camera kit Model: PST ... with microphone in camera. Item.DataTransmission Frequency ISM 2,400 MHz~2,483 MHz 4CH Modulation Mode FM Unobstructed Effective ... 50ohm SMA Intermediate Frequency 480MHz Frequency Stabilization ±100MHz 2.4GHz Wireless Cameras System (2 cameras+1 receiver)