This set of vintage magnetic  alphabet letters comes on a plastic tray with indentations for each letter so they can easily be organized when putting them away. Both the and the School Days Play Desk originally came with alphabet trays like this and had magnetic boards for the letters. 

The set shows some wear from age and is missing the letter "Q" but is otherwise in good vintage condition. All of the letters still have magnets on the back. 

Measurements:

Tray length: 8 inches (20.3 cm) on bottom, just over 8 5/8 (21.9 cm) inches on top
Tray width: 6 3/8 inches (16.2 cm)
Tray depth: 3/8 inch (1 cm)
Letter size: 1 3/8 inch (3.5 cm) tall, width varies by letter