A Big Strappin truck driver. Drives a big, shiny, hot rod diesel truck, admired for his professionalism, dedication to his profession, and preserverance.
A nerd, a dweeb. From the 1980's when the cool kids carried their backpacks using only one strap (over one shoulder). The geeks used both straps. Not relevant in a literal sense anymore, since the one strap fad seems to have faded. But still a cool sounding burn.
Why did you invite that spaz to the party? That dude is such a two-strapper.