UNITAS 501 Brand UNITAS Caliber 501 Size 16 1/2 Function Version Hands 1,15x2,00 Stem 9026 Stem (subs.) Stem (2 pce) Balance staff 35706 Balance staff (subs.) Mainspring (subs.) 1,50x15,0x0,12 Mainspring (subs.) Battery WatchpartsPart NocaliberdescriptionoriginalArtno.401Winding stem8029026723Balance staff ST -shock-absorber80235706