Alcance
                            ISO 3764:2016 specifies the types and fitting dimensions of mechanical and electromechanical watch-movements.This International Standard is applicable to the five following types of movements:-      Type 1: round;-      Type 2: shaped round;-      Type 3: round with double cutting;-      Type 4: 5 �′′′;-      Type 5: 6  � 8′′′.