The extent of the collection is given by counting the number of units it contains.  A separate line of physical description is provided for each generation or access term represented in the collection.

245 05 $a [The Barbaralee Diamonstein-Spielvogel Collection of talk shows with prominent people in the arts, 1976-1986].

300 ## $a 7 videocassettes : $b sd., col. ; $c 3/4 in. $3 viewing copy.

300 ## $a 17 videocassettes : $b sd., col. ; $c 3/4 in. $3 master.

300 ## $a 2 film reels : $b sd., b&w ; $c 16 mm. $3 pos.

If a collection contains materials of various physical details in the same generation or access term, then that information can be recorded in a single line of physical description for that generation or access term.

245 05 $a [The Mary Marvin Breckinridge Patterson Collection of her films and home movies, 1927-1976].

300 ## $a 7 videocassettes : $b si., b&w, col. ; $c 3/4 in. $3 viewing copy.

300 ## $a 4 film reels : $b si., sd., b&w, col. ; $c 16 mm. $3 viewing print.

300 ## $a 45 film reels : $b si., sd., b&w, col. ; $c 16 mm. $3 answer print.

See also:

Appendix C4.  Descriptive cataloging

Appendix C:  Collection-Level Cataloging