No, it will NOT work for your T5s. It's a T12 ballast. Ballasts are lamp specific. T5s are either Standard Output or High Output, 24w is a 2ft HO. You will need to get the right ballast for the lamp you want to use. (I'm an architectural lighting designer and work with this stuff all day.) T5s are generally a much better choice than T12s as they are much more energy efficient (more lumens per watt). If it does happen to light a T5 (which I doubt it will) it will either burn out the lamp or ballast after a short time. Also, one of the functions of a ballast is to limit the current in the arc going through the lamp. Without it the current will rapidly increase until the lamp experiences non-passive failure (iow: it explodes). You don't want to take that chance. Also, it looks like the unit has sockets which certainly will not work with a T5 due to the pin configuration.