The official Grind Style Calisthenics apparel features four elemental hexagons with each one's six sides representing the six fundamental tension chains. Each one sybolizes progressive calisthenics, suspension Calisthenics, weighted calisthenics, and isometric training which are the 4 disciplines of G.S.C. Custom designed graphic is printed in vivid color and high resolution using state of the art color transfer technology. Shirts are made from super soft 100% combed ringspun cotton. Printed in the USA.