Impact testing determines the amount of protection to the toe under various foot pounds of force. Compression testing determines the amount of static pressure a steel/composite toe cap can withstand. Our boots are I75/C75
Footwear is constructed of materials that, when in contact with properly grounded floor surfaces, will safely discharge static build-up through the shoe to the floor. Our testing experience contributed to the SD standard established in Section 6 of the ANSI Z41 and carried over to the current ASTM standards.
Built with an outsole design and materials that help provide slip-resistance and traction on various surfaces.
ASTM F2413 protective toe classification
ASTM F2413 static-dissipative standard
Moisture-wicking mesh lining
MARK II ASTM F1677 tested slip-resistant outsole
Removable EVA cushion footbed insert with sponge rubber heel wedge
A D width is a medium width. This is the width for an average width foot. The 3E is an extra-wide width. The specific difference varies per size and generally by shoe as there is not standard for width as there is for size which is based on length. The difference is very small, but can make a large difference to a person with a narrow or wide foot.
Here is a good article to help you better understand widths.