Stock Clearance - Buy Fast Whilst Stocks Last! This Philips HF-R 140 PL-L dimmable ballast runs 1 x 40w 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 HD-f ballasts are commonly used in offices. These units are for use with installations with emergency back up.