ʻO ka mea TPU ka polyurethane thermoplastic, hiki ke hoʻokaʻawale ʻia i polyester a me polyether. ʻO ke kiʻi TPU he mau hiʻohiʻona maikaʻi loa o ke kiʻekiʻe kiʻekiʻe, kiʻekiʻe elasticity, kiʻekiʻe ʻaʻahu kūpaʻa a me ka ʻelemakule kūʻē, a loaʻa iā ia nā hiʻohiʻona maikaʻi loa o ka mālama ʻana i ke kaiapuni, non-toxic, mildew proof and antibacterial, biocompatibility, etc.