New developing fabric heat seal label heat transfer paper/ film for most of active/underwear garment clothing CARE & CONTENT instruction's label for permanent I.D..
It's more comfortable & cheap comparing woven/printed lable, which offers brand and variable information without a sewn-in label, good washing fastness after transferred.
Heat transfer labels are best on sporty t-shirts, athletic wear, or baby items like newborn bodysuits. The heat transfers are easy to apply by a regular household iron or an industrial heat press (recommended for best results).