This tee was found in winter 2015, at JC Penny stores. It's dark blue, with 2 sewn-on hot-green stripes for each short sleeve. It has Boom style Sonic (he's in CG) standing with hands on hips for the design. His name is spelled out vertically in more hot yellow-green, & the Boom logo appears small, under one foot. (That band of lines to the right of him is a size sticker)

It's difficult to see but it says "Full Speed" vertically down one edge near Sonic, giving the shirt it's name "Full Speed Sonic Boom". This should be about 8 to 9 dollars in the boys/teens area.