good value prices in 1767

The optical quality of this objective have been discussed extensively in critical so I'm going to wear my approach on retail "forgotten". First surprise if the two rings rotate which makes sense, but the goal is or extension can not be reduced which is a destabilizing hair, it should certainly allow a better aging, it is true that the finger does not pass between the ring and the stone, I will ask the question, but why try to put them there, there is room elsewhere sufficiency ...