Extremely rare 1987 red Grateful Dead pullover sweatshirt. 

Shirt reads: "Tandem Deadhead" "And the music never stops" with an artwork image of tandem bicycling man and woman skeletons.

Unknown how many are in existence, but as far as the internet can find, this shirt doesn't exist at all, so it's extremely rare. 
It could possibly be the only one.
Made in the USA by J.C. Supply inc..

This may be a crossover with Tandem Computers, a 1970's silicon valley-based financial computer security software company. 
They were known for their "NonStop" software, which coincides with the "and the music never stops" quote on the shirt.

Very good vintage condition. A loose thread on the collar, and some light wear to the graphic print, see pictures for details.

**Shirt will ship FULLY INSURED with SIGNATURE DELIVERY**

Exact Flattened Measurements:
Manufacturer's Size: Medium
Length (shoulder to bottom hem): 24"
Shoulder width: 19"
Chest width (underarm to underarm): 20"
Waist width: 19"
Hem/waistband width: 17" (elastic)
Underarm to bottom hem: ~14"
Sleeve Length (topside): 23.5"
Sleeve Length (underside): 20"