The Seiko NH34A, also known as NH34, is a well-regarded automatic watch movement known for its affordability and GMT complication. Here's a breakdown of its key features:

• Japan-made automatic movement: It gets its power from your wrist movements and features a bi-directional rotor for automatic winding.

• GMT function: The most notable feature is the addition of a 24-hour hand, allowing you to track a second time zone simultaneously.

• Reliable and durable: It has 24 jewels for reduced friction and wear, and a Seiko Diashock shock resistance system.

• Decent accuracy: Expect an accuracy of around +40 / -20 seconds per day.

• Power reserve: It offers a power reserve of approximately 41 hours after a full wind.

• Hacking seconds: This allows you to stop the second hand for precise time setting.

• Date complication: It also features a date window typically located at the 3 o'clock position.

• Interchangeability: Shares similar dimensions with the popular Seiko NH35 movement, making it a potential upgrade option for existing NH35-powered watches with some modifications.

Overall, the Seiko NH34A is a solid choice for those looking for a reliable and affordable automatic GMT movement. It's commonly used in Seiko 5 Sports GMT watches and is popular among watch modders due to its interchangeability with other Seiko movements.