Just fine for masks!
Id been hoping to get the flat 1/4 elastic that is used in the directions for making most masks, but had to settle for the cord. It turned out just fine, though my sewing machine has some difficulty coping with the bulges at the corners where pleats and knits meet. The cord has held up beautifully in the wash, however, which seems to have been a problem with many elastics. All in all, Id buy it again without hesitation!
Mandala Crafts Elastic Cord Stretchy String for Bracelets, Necklaces, Jewelry Making, Beading, Masks