Tekton Flat End Hex L-Key Set, 43 Pieces, 0.050-3/8 Inch, 1.3-10 Mm

Tight Fit with Fasteners – In order to create a reliable, tight fit with fasteners, our L-keys are slightly larger in size with narrower tolerances than most competitors that follow the ASME standards Two Measures of Tolerance Control – We measure our hex key tolerances from point-to-point and side-to-side to ensure the highest standards of dimensional accuracy and consistency 8660 Steel – We make our L-keys with 8660 nickel chromium molybdenum steel that's heat-treated to 54–58 HRC to produce tools that are hard, but not brittle