I have a new in box kbt1 internal battery option for the k1. I unwrapped the speaker and the top and made the errata sheet corrections and then decided not to use the option in my k1. I will trade for a kts1 or make offer? I will entertain a trade before a sale. Thanks for Reading Reggie k6xr 48 years operating K1-4 01512 norcal 2306 qrp arci 8701