The UL 1989 UL 1418 Impact Test Ball is a 2-inch steel sphere that weighs 535 grams.

Specifications:
Impact Test Ball 2 Inch
535 grams Weight 50.8 mm Diameter
1.18 pounds Weight 2 inches Diameter

The Impact Test Ball is a specially machined ball to test impact resistance according to International Standards. It is made of chrome-plated steel for durability, and is fitted with an eyelet to facilitate testing for pendulum applications.

According to UL1989, UL1418 and other.

The point of suspension is one inch (25.4 mm) in front of he panel, h is 16.25 inches (412.8 mm). the diameter of the steel sphere is 2 inches (50.8 mm). and the mass of the steel sphere is 1.18 lbs (0.535 kg mass) and it is to hbe released from rest.