You got the type 66 401 1. It was first released in 1980. The caliber of movement is 66, basically the same, Aurelian described. The only difference is the missing date functionality.

It's a nice hand wound watch. Do you want to know anything specific about it?

Your watch has the type number 55 056 1 (Originally 014 056). It was first released in 1960, so it has to be slighltly younger then you suppose. Prim, or it's mothercompany Elton, formally Chronotechna, released it's first watch in 1954, so it's a pretty early piece in the company's history.

Judging from the pictures, your watch seems to miss the second hand. It should be pretty easy to have it replaced in Czech Republic. They do very good renovation services in the factory of Elton themselves, yet are very expensive, there are a few alternatives, that are a lot cheaper.

The book Aurelian mentioned is called "Primky" and has been written by Libor Hovorka, ISBN 978-80-7577-584-9. You'll find your watch on page 205.

However it's a very nice watch with a very nice story. Enjoy it.