About the Design:

Obverse:The profile of President Abraham Lincoln since 1909, the centennial of his birth.

Reverse:  Union Shield or Lincoln Memorial 

Proof Coins
The term "proof" refers to the coin's finish. The Mint recognizes a proof coin as “a specially made coin distinguished by sharpness of detail, usually with a brilliant mirror-like surface.” Proof coins are struck at least twice and treated with special dies which make their features more defined, detailed, and glossy.

Diameter    19 mm
Thickness    1.5 mm