The CM500 works extremely well with the Icom 7300 with very good audio reports (which is why I bought it after hearing others using it on their 7300). I no longer have the 7300 (which was my back up radio), so the CM500 was only used a few months (and very few hours of use) and is excess to my needs. However, it works well with other radios, Icoms (7610, 718, etc), Yeasu, Kenwood and will work with a FLEX 6500 (it has an Electret mic element and requires DC bias to operate). I used a Heil adapter which allowed bias voltage, but it was sold with the 7300, sorry. $40 shipped Priority Mail, which saves you about $30 if you had bought new one. USPS M.O. or PayPal.