The Burris Trumount Bases are designed to utilize the turn-in front and windage rear Standard Burris rings. These bases are machined from solid steel and are strong and lightweight. The reversible style bases enable the user to place the ring .850 forward or rearward to more easily accommodate long range scopes with large objective bells. Reversible sets are great for varmint, tactical, and long range setups.
Sinclair, Issue:5B, Page:205