A limited quantity of 8,802 specially made Proof half dollars were produced at the Philadelphia Mint in 1939. These premium-quality collector versions of the 1939 Liberty Walking half dollar were struck using specially buffed and polished Proof dies and coin blanks. Each Proof is struck at least twice, at slow speed and with extra pressure. The result is the magnificent Proof finish of frosted, sharply struck design images contrasted against shimmering mirrorlike surfaces.