Base Section 2 : The largest section of an extension ladder; it acts as the support for the upper section(s) when in the raised position. See: Bed Ladder
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}