HUSBTC - Big Ten Conference Expansion Coin. This officially licensed, 2" diameter, solid brass coin was minted in recognition of this historical event. Description. New official Big Ten coin featuring all 12 members and new conference alignments. Approx. 3 inches in diameter. Made of Brass. Write a review. This weekend, the Big Ten is honoring the two punters in a special way. The conference has produced commemorative coins featuring Foltz and Sadler — who.