Half-width red lines, when used, indicate package separations within a tray. Some mailings do not have package separations. Trays must be full if possible. This is to keep mailpieces from tumbling in the tray. The front of the tray is the end which has a tray label holder affixed to it.
Mail is placed into the tray standing on edge facing the front.
Tray codes indicate into which tray mail must be placed. Codes consist of one or two letters, such as A, B, C, etc., for barcoded mail, and NA, NB, NC, etc., for non-barcoded mail. Tray codes are printed at the right end of the top or bottom line of each tray label and on the right end of the first mailpiece label for each tray or package. You may have several tray labels with the same code if you have too many pieces to fit into one tray. Begin at the last label printed at the end of the label strip.