This watch is the Seiko 7A28-7000 from 1983. It's a quartz chronograph that times till 1/10th of a second. The removable block on the right side houses the chronograph pushers and on the left are the Split pusher and crown. It was designed by Mr. Giugiaro...
Normal pushers for the chrono on this model Wacky offset on the watch case relative to the bracelet Limited edition but each color was its own "edition" ...