Replacement 13 Watt Full Spectrum Bulb

This is the new 4 prong 13W replacement bulb for all 113.157 lamps sold since early 2011.  We currently can no longer get the old 2 prong replacement bulbs for lamps 113.157 & 113.160. The 4 prong 13w replacement bulb will not work with the old 2 prong 13w 113.157 sold before 2011.