what is the bar length?

My 14" XL uses S52T, there are other chains possible, this is the least aggressive, safety chain.

You probably have at least one shop in your town that sells and repairs lawn equipment. Probably listed in the yellow pages under lawn mower repair & service. Take your saw to them and they can tell you which chain you need and if they don't have it they can make you up a custom chain on the spot. They may not be as cheap as a lowes or home depot but it is 99% sure they will know exactly which chain you need, compared to 50-50 at the big boys. Just remember that if you put the wrong chain on then very shortly you could be still looking for a chain and a new bar also.

Take it to a saw shop and have them set you up. "Finding" a chain isn't rocket science - determine chain pitch, drive link gauge (thickness of the drive link), and the number of drive links you need for your loop to be the right size, and you're off to cut wood!

It is probably regular 3/8" pitch chain, which is about as common as it comes. Most XL-12/SXL that I've seen have 3/8" .050 gauge chain, unless someone intentionally set it up with something else. Mine took 59 drive links for a 16" bar with an Oregon ProLite bar, though your mileage may vary.

Like computeruser said, there should be no problem. If you still have not been able to find one, I stock them.
Count the drivers on the bottom of the chain. With a standard 16" Bar you should have 59. Avoid the Lo-Profile 3/8 as that is for the low power saws. With the torque your saw has you should use Semi-Chisel or Full Chisel. $16.97 or $18.47 + $4.85 shipping.
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