Parker Hale, Bisley Works, vernier PAT. No. 426027-35 .
Vernier click adjustment for lateral and vertical movement and with a variable aperture.
These were the sights we used for SRB competition shooting with the .303 P14 rifle.
This item is in perfect mechanical order.
I was Cumberland and Westmorland County rifle champion at 500yds in 1956 using one of these mechanical masterpieces.

25 post paid.