FEATURE ?Height 3.5mm,The volume is compact at about one-fourth of the former product(HC-49/U) ?A resistance weld completely sealed typed. ?The frenquency stability is good.the reliabillity is heigh. ?Copes with high density mounting and is the optimum for mass production ?Height 4.0mm, or 3.0mm,compact crystal unit for surface mount ?Able to by means of a metal case and completely sealed high resolution characteristics