The slots are for the insertion of a cotter pin to secure the nut when used with a drilled shank fastener

1/4 L9 USS Tension Flatwasher Yellow Zinc Plated Domestic USA (100)

Our inventory has been carefully curated to include all the fasteners service professionals and do-it-yourself enthusiasts might need

engineered washer and LOK-Nut

5 x 140 Hex Cap Screw 8

1 1/2 L9 USS Tension Flatwasher Yellow Zinc Plated Domestic USA (120) SNAPSKRU Drywall Anchors The slots are for the1 1 2 L9 USS Tension Flatwasher Yellow Zinc Plated Domestic USA (120) . L9 High Tension USS pattern flat washers are designed for use in high stress, severe service environments. The highest mechanical strength off the shelf fastening system available, its special features control torque tension characteristics to develop high clamp loads when using properly controlled tightening methods.