Strela 3017 KL1 chronograph, this particular model is known as the first watch in the open space. Soviet astronaut Alexey Leonov wore Strela Class 1 when he stepped out of Voshkod 2 and became the first person to leave spacecraft and conducted a 12 minute spacewalk. The event took place on March 18, 1965.
My watch was produced in the early 60’s and seems like it was used in former Czechoslovakia. Unfortunately I was’nt able to establish what is SVB and Ostrava is a town in today’s Czech Republic. Please notice that the case is typical for this model and the lugs are slightly thinner and rounded comparing to other watches with 3017 inside.