Review on VEIREN 100-Piece Adjustable Buckle Elastic Bands For DIY Crafts And Garment Sewing, High-Stretch Cord For Earloop Lanyards, Earmuffs, And More - Black by Kevin Harmon

It is always tough to guess the size needed for the elastic as each mask hits a person's face at a different point. This allows the wearer to adjust it as needed. The package stated "about 100". I had 98 and that was close enough for me. The black ones were very slightly shorter than the white ones (about 1/4 inch difference). The stretch is good. It is flat and easy to sew across (unlike the round corded ones). They are very comfortable on your ears. I have not tried them on young children but will do so tomorrow. If needed, I will adjust my review.