Seiko 7820-0020 Watch Guide The Seiko 7820-0020 is a watch model based on the 7820 movement.Parts List330N08GN00crystal45M44NN1crownOther models with the same movement7820-00107820-00307820-50007820-50107820-50207820-50307820-50407820-50507820-50607820-50707820-50807820-50907820-51007820-51207820-51307820-51407820-51507820-51607820-52107820-52207820-52307820-52407820-52507820-52607820-52707820-52807820-52907820-53007820-53207820-53407820-53507820-53607820-53807820-53907820-54007820-54107820-54207820-54307820-54407820-54507820-54607820-54707820-54807820-54907820-55007820-55107820-70007820-70107820-70207820-70307820-80007820-80107820-80207820-80307820-80407820-80507820-90007820-9010