A SINGLE UNIT is described in the same way as the MULTIPLE COMPONENT UNIT. The SINGLE UNIT uses the identical format of a sub unit in the MULTIPLE COMPONENT format. The SINGLE UNIT begins with the section # and letter (which is always the letter A) followed by the reference, dimensions and descriptions (parts 1 thru 4) as listed above. As you can see, MULTIPLE COMPONENT UNITS are groups of SINGLE UNITS.
The GLOSSARY OF TERMS defines the details and parts that are listed in the description area of each MULTIPLE COMPONENT, SINGLE UNIT or SUB UNIT.