Model 2PBR is a 4-wire power block which works with 2-wire scanner blocks and logic modules and offers an SPST "hard" contact for switching heavy ac or dc loads. Model 2PBR2, also for use with 2-wire scanner blocks and logic modules, uses a 3- or 4-wire hookup with SPDT "hard" contacts for switching heavy ac loads. Model 2PBR actually requires a 4-wire hookup and model 2PBR2 requires a 3- or 4-wire hookup, even though they only work with 2-wire scanner blocks and logic modules. Both are powered by 120V ac across terminals #1 and 2. The 2PBR offers an SPST "hard" relay contact between terminals #3 and 4. Model 2PBR2 is an SPDT version, with both contacts common to terminal #1: terminal #3 is a normally open output, and terminal #4 is normally closed. These configurations allow MULTI-BEAM sensors to directly interface large loads which draw more than 3/4 amp like clutches, brakes, large contactors, and small motors. Model 2PBR can switch both ac and dc loads; model 2PBR2 switches the ac line voltage to an ac load (see connection diagrams). The 2PBR and 2PBR2 also eliminate the problem of voltage drop from series strings of sensors operating low voltage ac loads.