I ordered the above covers for my S&B 50mm objective and eye piece.
Because I have low mounts I found out the hard way that I could not fit the objective cover on. The objective screws on to your scope's objective thread forming a solid seal and is very strong, it is specific to S&B but other adapters can be bought I believe. To my cost I dismantled the objective hinge to see if that would make a difference however I still couldn't get it to fit. In the process I have not been able to get the cover to flip back up due to my lack of knowledge of the set up and positioning of the spring. I cannot see any damage to it.
I returned them to the retailer and they could not sort it out and would not refund me, nor work with me to off load them. They returned these to me (plus postage!!) and now I have them for sale as they are no use to me.
I believe these are more suited to PMII's etc.
I paid £108.
I accept the objective is not flipping up now but I'm sure someone out there could get it to work.
I'm after £75 delivered. I can post pics later if needed.