- Circuit Breaker Locking Device – for Single & Multi Pole MCB’s & MCCB’s. Opened & closed with Screwdriver. Color: Blue. DESCRIPTION: ● ABS construction, Temp: -20 upto 90 Deg.C ● Tightens on toggle with screwdriver, locks several different MCB models. ● Locks certain models of bottle fuse holders. Weight: 0.020 Kg. (20 gms)