I just installed one 2 hours ago, but it's a Leupold that I got from Brownells yesterday.
Leupold bought Redfield, so unless you need (for some reason) the little Redfield stamp, just buy a new one from Brownells.
It's made by the same people, and it's the same base, other then the stamp and the package.
Brownells Stock Number 526-261-750