PR4, 6 and 8 movement.
The Seiko Presage line up is indicated by PR4, PR6 and PR8 referring to the movement.
PR 4, 6, and 8 indicates the technical innovations and amount of parts in the movement, with the PR8 as there most advanced movement. It’s remarkable that in other countries the Seiko Presage series is classified in the Basic Line and Prestige line even though we are talking about the same watches.
The movements are completely made in house with own technical innovations like Diashock, Magic Lever and a Spron mainspring.
Diashock is a device that protects the balance wheel from shock and vibration. The jewel anchoring the balance staff is attached to a hairspring and, when the balance staff is subjected to a strong shock, the elasticity of that hairspring absorbs it.
Magic lever increases the winding efficiency of a watch and shortens the time needed for the main spring to become fully wound. This ingenious V-shaped lever allows all the energy generated by the oscillating weight’s motion, whether clockwise or anti-clockwise, to be transferred to the main spring.
Spron mainspring and hairspring alloys are exclusive to Seiko watches. Spron features superior elasticity, strength, and corrosion and heat resistance. The Spron family of alloys was originally developed jointly with the Metal Materials Laboratory of Tohoku University and, today, the high performance characteristics of Spron have led to its use in a wide range of fields, from electronics to medicine.
The movement is reliable and of a high technical quality for this price range. Unfortunately the finishing of some parts is poor.