Help with cable

Hello - I was hoping someone could help identifying some bulk black cable that I have laying around. I would like to add a 3 prong plug to it and use it as a extension cord, but am clueless on what is printed on the outside cover.

Here is what is printed:
ul c(ul) SJOOW 3/C 18AWG(0.824mm2) 105C VW-1 300v E215210 100281-001

I assume it means 18amps and 300volts but wanted to get some advice from someone that knows what they are doing before I catch something on fire. I would say that it is about 12'-15' long.

Thanks in advance.
PB