i was just checking my mail last night and i saw the vostock europe watches that roy had just got in,i just could not help myself,i bought the black dial with slide rule bezel ref 5335017 straight away,i should have it by tuesday, if someone has the time could they explain how a slide rule works or direct me to a site or something to explain one,i have been told its something to measure time and distance, last night late on i had to come clean and admit to my wife, "do you know that watch that i was showing you earlier" her response"yes" my reply"i bought it" her response to that "