Cableware offers a series of gauges to measure the tension in rods from .172 to .375 inch in diameter over a range of approximately 5 to 25 % of the breaking strength of the rod and provide an accuracy of + or - 5%. The "Professional Model" RT series provides an increasing durability, accuracy and convenience of use. Manufactured of rugged anodized aluminum, this gauge is corrosive resistant and will give years of service. Detailed operating instructions are included with each tension gauge. Operates in the same manner as the Professional Model Series. For rod sizes .172, .198, .225, and .250