Beyond grade 1 performance is the hallmark of the mechanical and electrified ND Series locks. The locks are put through extreme levels of testing and are proven to withstand 3100 in. lb. of abusive lever torque - more than 2-1/2 times the grade 1 standard requirement. Offset lever pull testing up to 1600 lb. assures you of the lock's superb resistance against pry bar attacks. More than strong, ND Series is built to last and shows nearly zero droop or wobble after 16 million cycles. All ND Series locks including electronic and ligature-resistant trim use the common cylindrical ANSI-161 door preparation making them easily interchangeable. They are ideal for all new construction and retrofit applications where grade 1 strength and security are desired.