This booklet is targeted to K3 owners who now have ÒThe Elecraft K3 Ð Design, Configuration, and Operation, 2nd EdÓ book and who are wondering about or are planning to upgrade their K3 with K3s components. It offerÕs KE7XÕs recommendations and describes the operation of the new KIO3B I/O Interface and the new KXV3B Receive Antenna and Transverter Interface. Complete coverage of the K3 with original K3 components plus selected K3s components can be found in "The Elecraft K3 and P3 -- Design, Configuration, and Operation, 3rd Edition".