Tube socks were pretty darn popular in the 1970s. Simply put, back then they were socks, knitted into a single long tube that was sewn squarely at the bottom, so that they had no clearly delineated heel or ankle region. As a result, they were pretty much one-size-fit-all and were often sold in plastic bags of six or twelve pairs, although the nicer ones were more costly and sold individually.
Their popularity with sportsmen had actually started back in the 1960s, when striped ones became very fashionable in locker rooms as jocks could proudly display their team colors. Gradually, guys used them for more than their intended purposes, as the long tube became handy to use as a sturdy storage container for miscellaneous small junk, and the open top could easily be tied into a knot. Well, it didn't take some guys very long before they began to strip naked and stuff their personal "junk" into the tube and pose for a handy Polaroid camera, leaving viewers with the fantasy about how big the dick inside that ribbed cotton tube actually was, and to show off your physique without actually showing the main event. The socks may have changed over the decades in terms of design and colors and fabrics, but THAT tradition continues today.
