Features Available with single door, double door, four door. Working fast and efficiently, yielding even proofing with full loads or partial loads. Sinmag proofers are built with durable components and reliable, easy-to-use controls. Sinmag proofers make the process of proofing easy and consistent, keeping uniform temperatures throughout the racks and even constant airflow. Assemble using a cam-lock design, minimizing installation time.