KV was Weaver's first entry into Variable Scopes around 1958 as I recall. Really was a pain in the butt, you had to take a small screwdriver/blade, and after removing the turret cap for the power adjustment, turn the turret to different power settings. Problem was they were notorious for point of impact changes and you could not sight a rifle in then move the power adjustment up or down, then back to EXACTLY TO THE SAME SETTING, WITHOUT A CHANGE OF IMPACT. HTH