In February 2011, we entered the yacht industry with the sale of our marine hoist to Sunbird Yacht Company. Entering an additional market with our marine hoist demonstrates our focus on diversifying our revenue streams as well as our ability to utilize our core competency of engineering high quality machines that provide a value to our customers. We believe we will be able capitalize on our entry into this market as well as penetrating the yacht and wind power industries that we entered earlier this year.
Management issued revenue guidance for the second quarter of 2011 of approximately $8 to $10 million. As of March 31, 2011, Wowjoint's backlog of signed contracts totaled approximately $25 million. As of May 19, 2011, the backlog of signed contracts has risen to $29 million.