I have a couple Nikon Scopes and kept the warranty info.
They offer a "Lifetime full warranty."
Even if you are not the original owner, they honor it.
No receipt required.
That is about as good as it gets in my opinion.
Obviously if you modified or misused the product, the warranty will not apply.
Nikon Inc. Warranty Department
841 Apollo Street, Suite 100
El Segundo, Calif. 90245-4721
Phone: 1-800-645-6678
I might be a little biased because of my photography background, using all
Nikon gear but I really love their rifle scopes. Including the
Prostaff series.
Don