• Once the coil spring has been accurately formed, the heat tempering components of the machinery firmly grip the spring and apply 50 ampers (amps) of current strength to the spring. This raises the temperature of the coiled spring to 600 degrees Fahrenheit ensuring the wire will retain its design, shape and resilience. By causing the spring to "remember" its shape through the heat tempering, the spring will perform as desired for a much greater period of time than a non-tempered spring.
• The wire used for heat tempered coils is carefully chosen to meet quality factors such as close tensile strength ranges, uniformity in guage and roundness, uniformity in cast and consistent chemical composition.

• Heat-tempered springs will return to 98 1/2 half percent of their original height after being fully compressed. Independent tests have demonstrated that a freestanding 7 1/2" high heat-tempered coil spring will return to 7 1/4" high, or only 1/4" loss of height, after being fully compressed. Non-heat-tempered springs will return to only 85 percent of their original height after being fully compressed. Independent tests have also demonstrated that a freestanding 7 1/2" high non-tempered spring will lose as much as 1 1/8' in height, going to 6 3/8" high, after fully compressed.
• Heat-tempered springs will retain their correct and specified coil diameter, providing dependable support and resistance over the life of the mattress. Non-tempered springs will allow the diameter of the springs to "open up," or become larger. This causes softening of the mattress in the locations where it receives the greatest amount of use. The weakening of the non-tempered springs considerably reduces the opportunity for proper rest and support.
• Heat-tempered springs assure that the spread, or distance, between each turn of wire in the spring will remain exactly as produced. This guarantees that the resilience remains constant through the years of use of the mattress. Non-tempered springs will allow the spread, or distance, between turns of wire to decrease, which reduces the resistance and height of the springs with usage. This leads to sagging in the finished mattress over time.

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