Anti-two-block (ATB or A2B) warning systems are used to warn or prevent the crane operator from two-blocking the crane.

Two-blocking is a dangerous condition where the hook block is raised until it contacts the boom tip. 

Two-blocking is dangerous to personnel and can cause expensive damage to crane booms and equipment.  

Anti-Two-Block warning systems are the most basic operator aide every crane should have.  We offer ATB systems to fit every type of crane and application.

Anti-Two Block Systems