I got a rifle scope that has covers attached to each other by a black stretchy string.

The problem is the scope has a sunshade that's about 3 inches long.  The covers only fit on the scope without the shade.  I want to leave the shade on all time and yet have the covers fit. 

I was able to pop out the plugs from the caps and found that the current stretchy strings just have a knot and the plug holding them in.

So, if I could find some of that type of string I'd just replace what I have and all would be good.