Fiberglass Square Tube Material Fiberglass Wall Thickness 0.25 in Color Dark Gray Inside Corner Shape Square Outside Corner Shape Square Outside Height 4 in Outside Width 4 in Inside Height 3 1/2 in Inside Width 3 1/2 in Overall Length 10 ft Maximum Temperature 150 Degrees F Resin Type ISOFR Standards ASTM E-84 Tensile Strength 30 000 psi Wall Thickness Tolerance +/-0.038 in Type Square Type Square Tube Length Tolerance +/-0.125 in Minimum Temperature -100 Degrees F