AutomAticAlly sets itself. AccurAcy: 1/10,000 of A second. Controlling rAdio signAl from NIST AutomAticAlly Adjusts clock for dAylight sAvings time, leAp yeAr, And leAp seconds. Highly visible bright second sweep hAnd. With NIST TrAceAble*. 30.5diA.x3.8Dcm.