The key to listening centers is the jackbox, the distribution point to the headphones. Califone gives more attention to this jackbox with features such as silver-plated contact points for a solid connection and moisture resistance, individual volume controls, and rugged ABS plastic housing for durability.

Strain-relief connectors assures they won’t be pulled out, even in the roughest school conditions
Permanently attached cord with 1/4“ and 3.5mm plugs attach to all media players
Individual volume control for personalized preferences
Rubber feet so unit will not “walk” or scratch desktop
Predrilled holes for permanent mounting