This is a winter turtleneck shirt. It's not often you see a Sonic design on this type of shirt. It says "Step it Up" in big red letters. It uses CG running Sonic in full color over the letters & a white spin/swirl for the background. The top and bottom are bordered with the 'speed boost pad' arrow like shapes. The design is unique enough with the CG that it looks fresh here.
The shirt itself is mottled pale gray. It has a zig-zag of orange/red thread at the borders of each sleeve & the bottom. This is thought to be a winter 2015 or 2016 item. Where is it sold?