All walkie-talkies released by retevis have a squelch function, which has a certain noise reduction function and the sound is clearer.
Retevis RT40 with Squelch Strict and Normal functions
Strict squelch: the call quality is very good, and the call distance is 1.4 kilometers
Normal squelch: the sound quality is also good, and the call distance is 1.7 kilometers