the front thread of your iris is removed with the factory spanner
501`s adaptor thread is screwed into the front of your iris
the iris and 501 are attached to your rearsight after loosening the rail carrier`s allen screw
the lens is inserted in the lens holder which can be removed from the carrier rail if required
the lens holder is positioned to the rear of your iris as required and locked on the carrier rail
our system allows alignment of the carrier to suit you
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