This is the 21.4Mc center frequency unit. It is in good working and cosmetic condition. Replaced a couple of capacitors in the sweep generator stage. I would like to trade it for a comparable T-100 (455kc, 100kc bandwidth), or T-200 (455kc, 200kc bandwidth) unit. Pictures available on request. Replies off-list, please. 73, ian K3IMW