This is my favorite accessory that I use with my EVX-531 radio. The audio is loud and clear and it is extremely lightweight and dependable.
MH-450S: Vertex Speaker Mic (shoulder microphones) with PTT and 3.5mm audio port. For use with Vertex 2-pin radios VX-231, VX-351, VX-354, VX-451, VX-454, VX-459, EVX-531, EVX-534, EVX-539.
Replacement for Vertex MH-450S, MH-360S or MH-45B4b microphone.