Structurelite C- Channel Extrusion is supplied in standard sized 1.25" wide x 2.125" high x 100" long 6063-T5 aluminum bars that are clear anodized. The 1.75" x 0.556" slot is centered to hold .375" material using the C-Channel installation Kit (SL-CHNLKIT). *Additional packaging fee will apply for lengths over 34".