By French Toast School Uniforms. Available in Regular, Husky and Slim sizes. Boys Double Knee Pant School Uniform. 60% Cotton/40% Polyester. Permanent press wrinkle resistant fabric, flat front, reinforced double knee, slide closure, three pockets and belt loops. 3 inch elastic band in the back in sizes 4-14. Slim size does not have the 3 inch elastic band in the back for sizes 4-14.