The MAC Tools Socket Tray you described appears to be a vintage red metal tray specifically designed to hold and organize your sockets. Here's a breakdown of its features and potential uses:

Features:

• Material: Red metal 
• Size: Approximately 16 inches long, 2.5 inches deep, and with a width that tapers from 1-3/4 inches to 1 inch.
• Color: Red
• Brand: Designed for sockets 
• Vintage: This seems to be a vintage item, no longer in current production by MAC Tools.

Uses:

• Organizing and storing sockets 
• Can potentially be used to store other brands' sockets of similar sizes 
• A vintage tool tray for collectors or enthusiasts of MAC Tools memorabilia