K head plug 2 pin; can't compatible with any Motorola or Midland two way radios, compatible with Retevis H-777 RT21 RT22 RT68 RT22S H-777S RT-5R RT18 RT19; compatible with Baofeng UV-5R series BF-F8HP BF-888S; compatible with Arcshell AR-5; compatible with Kenwood two way radio and more