There is really only 3 things that you need to know when shopping for a chain. And all of them can be measured by you withiut any special tools.
First is the chain pitch. There are several but the most common are .325, 3/8, and .404. Yours is listed as 3/8 low profile. (low profile means the cutters arent as big. And these take a 3/16 file to sharpen instead of the 7/32 that regular 3/8 takes). You can verify the pitch of the chain by measuring the distance of 3 rivets and dividing by 2.
Second thing that matters is the guage. The common ones are .050, .058, and .063. This is the thickness of the drive links that ride in the bar. Again, this is not saw or brand specific. Rather it is specific to the bar. It is usually stamped on the bar, but if you have a set of mics or calipers you can verify.
Third is the length of the chain. Easiest way is to count the drive links. Because NOT all bars of the same length take the same # of dirve links. A 20" husky small mount bar is usually 70 links. A husky larg mount bar of the same length is usually 72.
Once you know all three of the above, it makes it easier to buy chain. And I would be willing to bet that even a place like tsc has it in stock.