When it comes to a Sewn-On Greek Letter Hoodie, we know what we're doing! Our sewn-on letters are made of two-layer twill and Sigma Pi greek letters are stitched to perfection on our 50/50 cotton/polyester fleece blend mid-weight hoodie. This product isn't one of our Sigma Pi in this stitched 50/50 cotton/poly fleece blend hoodie.