Waygate Technologies Krautkramer mini-DFR [118-440-502] Delay Lines, 0.125 Inch (3 mm), 0.38 Inch (9.5mm). Waygate Technologies delay lines are short plastic inserts that sit between the active element and the test piece and which improve near surface resolution as well as protect the active element from thermal damage in high temperature testing. Waygate Technologies delay lines are for use with DFR and mini-DFR type delay line transducers. The delay lines are replaceable and available in different lengths to increase the versatility and longevity of the transducers.