The Prep Bible.
Both of these are rifle scope bases, but they are built for different guns and different materials. The Talley Picatinny Base P00252714 is a 0 MOA base made of steel, designed to fit the Tikka T3/T3X, and it uses Picatinny mounting.
The Weaver Top Mount Base Pair 48460 is made of aluminum, fits the Remington 700, and comes as a set of 2 bases with Unit Quantity listed. It supports both Picatinny and Weaver mounting, giving it options for the type of rings you attach.
Spec for spec
SpecTalley Picatinny BaseWeaver Top Mount Base
MaterialSteelAluminum
ColorBlackBlack
For Gun MakeTikkaRemington
For Gun TypeRifleRifle
MountingPicatinnyPicatinny, Weaver
Sport/ActivityHuntingShooting