When selecting an appropriate window function for an application, this comparison graph may be useful. The frequency axis has units of FFT "bins" when the window of length N is applied to data and a transform of length N is computed. For instance, the value at frequency ⁠ 1 / 2 ⁠ "bin" is the response that would be measured in bins k and k + 1 to a sinusoidal signal at frequency k + ⁠ 1 / 2 ⁠. It is relative to the maximum possible response, which occurs when the signal frequency is an integer number of bins. The value at frequency ⁠ 1 / 2 ⁠ is referred to as the maximum scalloping loss of the window, which is one metric used to compare windows. The rectangular window is noticeably worse than the others in terms of that metric.