abc offers carabiners in aluminum and steel, as well as in auto locking (self locking) and manual locking. Many of our carabiners meet the stringent ANSI Z359 requirements and OSHA's update to Walking Work Surfaces. Those requirements include a 3,600 lb gate and that the carabiners be auto locking. Look in product details for information about certifications and standards.

You can find auto locking carabiners here.