HPA 250-500/30 SD FX LThis is a TwinPack deal. You'll receive two (2) bulbs. The Original Isolde HPA 250 500 30 SD FX L is a high quality bulb made with the finest raw materials. It is designed to provide high actinic output and long service life. The optimized spectral output guarantees rapid curing and short exposure times with the industries best dot to dot quality. The 106 mm long HPA 250 500 30 SD FX L has a typical lifetime of 800 hours. optimized spectral output