I have both types, with and without the leds. Mike B. says the ones without the LEDs are for the XT. Mine is Part # 1390120 and it works not only on the XT but also anything else I plug it into. FWIW, so does the one with the LEDs which is Part # 1391401. And so does another with LEDs, Part # 1391580. They're just the best keyboards every which way.