เป็น แนวตั้ง หรือว่า แนวนอน
Traditionally, the horizontal chronograph operates by meshing between the second wheels and the chronograph wheel. Sometimes, their teeth do not mesh properly or the tooth profile was worn out making the operation out of sync. The result is that when starting the stop time, we might see the chronograph hand "jumps" a little before running normally. In high horological terms, the precision is compromised. The vertical clutch chronograph is a recent invention. It operates by friction between the clutch plate and the chronograph plate, just similar to what happens in a car's gearbox and the flywheel. They catch each other vertically and the transfer of rotational action is instant. Therefore, there is no "jump" and, in theory, there is no loss of precision.
Pros & Cons? it is about personal preferences, I guessed. The horizontal engaged chronograph is traditional, especially those that come with a nice-looking column-wheel mechanism as we can see in many expensive brands (say.....A. Lange n' Sohne or Patek Philippe). However, many others would use the cheaper cam-level system such as 775X family, less pleasing for some, but it is very robust. For the vertical clutch, it is hard to see since the clutch plate and chronograph plate are hidden from the eye due to their architecture. This concept is more about efficiency and precision (whatever it means to the owner) rather than aesthetics. How do we know? We need to look at the movement's model and find out its specification. OR, if we can see the movement itself (or those with a see-through back), we can just look at the movement's architecture krab.....wish this help.