The Line 6 PX2 is a power supply that can be used with a variety of Line 6 pedals including the DL-4 which is what I use it for.  It can also be used with pedals in the same line like the MM4 and the DM4.  This will also work with the Variax and the PODXT and I think that is about all that it will work with as it is a specified type of power supply.  It is nice that the power supply has the large part of it in the middle and has wires that will run from either way.  This way you can plug it into the wall or wherever easily and it won't take up more space than is necessary within a power strip.  I've never had any problems at all with this power supply as it has always worked great in tandem with my Line 6 DL4.  Of course this isn't a power supply that you go out and buy as a general power supply as you will only need it if you have one of the few Line 6 products that require this exact type of power supply.  The only bad part about this power supply is the price as I do think it is a bit over priced and you do have to buy it separately from whatever pedal or device that you are going to use it with.  There isn't all that much more to say about the Line 6 PX2 as it is a sturdy power supply that is nicely designed and will do its job.  If you have a pedal or another device that requires this power supply, rest assured that it will work well if you need it.  All in all this is a smartly designd pedal that although is expensive, will do the job that it is designed to do.