This Primus Miscellaneous Debris t-shirt is officially licensed and manufactured by Manic Merch. The front is screen printed on a black t-shirt made from 100% cotton.  No design is on the back.

Size,          Brand,        Armpit to Armpit, Top to Bottom
Medium     Tultex                   19.5"                29.5"
Large        Tultex                    21"                   31"
X-Large     Tultex                    23"                   32"
2X-Large   Tultex                    25"                   33"