LEXMARK 500 Sheet Paper Tray

for Optra Plus, 4039, 4029, 4019, or WinWriter 600 Printers

A4/11" Max. Paper Size, 550g Paper Weight Capacity.

This tray is meant for printing labels!  The sticker on the top of the tray reads:

WARNING!! LABEL USE ONLY HEAVYWEIGHT LABEL TRAY ADJUST THUMBWHEEL FULL +

This 550g weight is a midrange paper weight, as trays with 450g, 550g, 650g and 750g capacity were manufactured for these printers.