Bikinis were pretty good, except for the part where they do not keep the rest of the scope clean, and most did not attach to the rifle itself to keep them from flying off.
ScopeShield neoprenes solve it all, and are used by MuleDeer here and many other of the major contributors to the campfire.
Your SS 3-9X42 is a 13.1 inch scope which is fit by the ScopeShield SS12. (A 12 inch stretchable cover)
