HP Color LaserJet Enterprise M651 Printer series - Manual (Page 29)

Load the 1,500-sheet high-capacity input tray
1. Open the tray.
NOTE: Do not open this tray while it is in use.
2. Adjust the paper-width guide to the correct
position for the paper you are using.
LGL LTR A4
3. Rotate the paper-stop lever to the correct
position for the paper you are using.
ENWW Load the 1,500-sheet high-capacity input tray 21