Stock Clearance - Buy fast whilst stocks last This Philips HF-R 155 PL-L dimmable ballast runs 1 x 55w PL-L. This ballast's lamp power can be regulated from 1% to 100%, automatic stop start, automatic restart after lamp replacement, up to 75% reduction in energy consumption and quick programme flicker free start.The Philips HF-R ballasts are commonly used in offices. These units are for use with installations with emergency back up.