... movement WWVB Radio Controlled Alarm Movement, step movement Specifications:Model NO.: DM7820 (WWVB) - Step Second HandSize(MM): 78x65x20Other Relative Models: ... DM7920 (WWVB) - Sweep MovementDM7810 (JJY), DM7830 (DCF), DM7840(MSF) - Step Second HandDM7910 (JJY), DM7930 (DCF), DM7940(MSF) - Sweep Second HandFeatures ... (PCS/CTN): Size of Ctn.(CM): Radio Controlled Step Movement for Clock , WWVB