The low temperature environment where power tools are used is assumed to be up to about -10℃. But the flexibility comparison at -20 ℃ is adopted as the optimum evaluation condition to compare the flexibility in the low temperature environment(up to about -10℃). From the past, it is a test condition created by the result of trial and error in-house. (In the evaluation at -10 ℃ or 0 ℃, there was a discrepancy between the evaluation result (numerical value) and the feeling of use (sensuality), and they could not be matched.) In addition, it seems that it is easy to improve the flexibility by adjusting the composition with almost no effect on the cost, but if it is too soft, the cord will be loosely fixed by CordClamp, so in order to have compatibility with the current cord, we should aim for the same hardness.