The UB171 Fall Arrest Block has a cast Aluminium housing, making it suitable for heavy-duty use, even in harsh environmental conditions. The UB171 is fitted with a retrieval winch which can be easily engaged in emergency situations. The block is fitted with a Swivel-eye Karabiner, which also has a load-indicator. In the event of a fall, the swivel eye will pull out a short way, exposing a red collar.