There are two general categories of couplings to connect most types of hose: the permanent type (used primarily by equipment manufacturers, large-scale rebuilders, and maintenance shops) and the field-attachable type. Permanently attached couplings are cold-formed onto the hose with powered machinery.
The trail measured 2,168.1 miles in 2001. The total distance of the trail changes slightly from year to year as trail maintenance groups reroute the trail as needed. An Appalachian Trail thru-hike takes between five and seven months to complete the entire trail. (About 20 percent of hikers who begin the trail will complete it.) The average cost of an Appalachian Trail thru-hike is approximately $3,000 (about $1.50 per mile), not including gear.
While some people hike the AT in sections over many years, those known as thru-hikers attempt to complete the entire trail in a single season, a commitment that takes five to seven months.