This is a nice Seagull 1963 which is a reissued version of the Chinese Air force Mechanical Chronograph of 1963 . It has a nice chronograph Seagull ST19 with 19 jewels movement with heated hardened blue steel screws.
Seagull has now arisen as the world's largest manufacturer of mechanical watch movements, whose production cover a quarter of the total world production of movements. I call it the Chinese Seiko :).
Info about the specs of the Seagull Cal. ST1901; here.
If you want to read more about the history of Seagull; here.