DTI SmartBolts

DTI (Direct Tension Indicating) SmartBolts directly correlate fastener tension with color. Accuracy and reliably is ensured because the color change of the DTI Visual Indication System™ is proportional to fastener stretch — the only true measure of how tight your joint is (torque readings can be misleading since torque only measures how difficult it is to turn the bolt head).

The SmartBolts built-in visual tension indicator turns from red to black when proper tension has been reached — and is completely reversible for the life of the fastener.

DTI SmartBolts are Available in a Wide Range of Sizes and Types:

Fastener Types Hex Flange Socket Stud Other
Diameter (Minimum) 7/16” (M10) ½” (M12) 1” (M24) ¾” (M20)
Diameter (Maximum) 2 ½” (M64) 2 ½” (M64) 2 ½” (M64) 2 ½” (M64)
Length (Minimum) 1 ¼” (30mm) 1 ¼” (30mm) 3” (75mm) 3” (75mm)

DTI Visual Indication System™

The DTI Visual Indication System™ continuously measures and displays tension information. From loose to tight and back again, the system is reliable and repeatable through countless cycles of operation. It is compatible with a wide range of fastener types, and we can adapt it to fasteners of nearly every available grade, finish, and coating.


Our engineering team can design the DTI Visual Indication System to meet the specific requirements of your application. During the design phase, a Design Tension is specified. The Design Tension identifies a properly tightened SmartBolt.

Accuracy +/- 10% of Design Tension
Design Tension Range 30-90% of Modified Proof Strength
Operating Temperature Range -4F (-20C) to 168F (75C)