This Grateful Dead Bear Mountain t-shirt is officially licensed and manufactured by Liquid Blue. The front is screen printed on a tie dye t-shirt made from 100% cotton.  No design is on the back.

Size,          Brand,        Armpit to Armpit, Top to Bottom
Medium     Liquid Blue            19.5"               29"
Large        Liquid Blue             22"                  31" 
X-Large     Liquid Blue            23.5"               32"
2X-Large   Liquid Blue            25"                  34"