Is this an A-series or a T-series light bulb?
It is an older style Philips Halogena bulb meant to replace the typical incandescent bulb.  The lamp is a quartz halogen tube enclosed in a glass envelope that resembles an older style light bulb.  The 70 watt actual / 100 watt equivalent spec sheet for this style bulb can be seen here:

http://www.usa.philips.com/c-p/046677209698/halogena-energy-saver-household/specifications

In this case you have a 43 actual / 60 equivalent.  "A19" and "T60" are essentially the same thing.  "A" designates the original light bulb shape and "19" designates the diameter in eighths of an inch (bulb shape, 2.375" diameter).  "T" designates tubular shape, but unlike florescent tubes where the number indicates eighths of an inch, in this case the number is in millimeters.  "60" in indicates 2.36" diameter.  For all intents the two are interchangeable.

In the most recent version of this 60 watt halogen, Philips changed the glass envelope from metric "T60" to the english "A19":

http://www.homedepot.com/p/Philips-EcoVantage-60-Watt-Halogen-A19-Soft-White-Dimmable-Light-Bulb-4-Pack-426031/203637006