Item Description Assembly Length Tolerances (fractional inch) Tolerances (decimal inch) Up thru 12" 3/8" 0.375" Over 12" thru 18" 1/2" 0.500" Over 18" thru 36" 3/4" 0.750" Over 36" thru 120" 1" 1.00" Over 120" thru 25' 1.5" 1.50" Over 25' thru 50' 7" 7.00" Over 50' thru 100' 12" 12.00"