The purpose of the Mower Deck or Cutting Deck is to safely enclose the grass cutting operations of the mower. The mower deck can range in size, durability, and shape. For example a residential zero-turn mower might have a 32" stamped metal deck, while a commercial-grade mower could have a 72" fabricated deck welded from 10-guage steel. When picking a replacement mower deck, make sure to note if you are purchasing a "Deck Shell Only" or a Complete Deck (which also includes spindles, pulleys, covers, etc.).