Yarn Choice Help Please

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I want to make my DH a dickie and am looking for black sport weight yarn. I want it to be machine washable and dryable. I am not sure what to use or where to get it. We have a Michael's here and that's it, but I have no problem with ordering it online. I don't know what type of yarn to use since I want it to be light weight to wear under flannel shirts sometimes. I am soooo confused! There is too much out there.
Help!!