Benefits:
+ Good workmanship
+ A few restricted sight
+ Easy to install and again to solve slightly
Disadvantages:
- No :-) (or possibly attach the dust-free can be problematic depending on the environment)
Another useful accessory for the Sony A7 / r / s and this film can be seen in the following YouTube video, entitled: "Sony A7 / r / s Accessories, Accessories" - see> Marks check.