It is a tape measure not a 'strap', the little nobs are at click settings of the focus mechanism. You can use it as a strap, but it is your rangefinder as well. Otherwise we would be OT, he, he, he
Mine is ok. I have to avoid finger printing the optic,... Supposedly the other XA need AgO batteries but mine does not seem to mind genric Ch batteries much.
There is a site on XAs try google...
For the last 13 months I've only used a Kiev (or Contax), apart from folders, Fed's, Zorki's, M2, etc.,... and a digital to record dismantle sequences...