Block trolley with two ball-bearing wheels, designed to run on the lower flange of all normal standard beams, regardless of profile. Allows easy passage through curves. Equipped with anti-drop protection that prevents the block trolley from falling off the beam in the event of e.g. axle breakage, collision, etc. Supplied adjustable within the limits specified in the table. Minimum curve radius 0.5m. Without mechanical transport device. Table of different beam types.