1. Kev tsim kho yooj yim thiab ceev: tsis tas yuav tsum muaj lub cushion
2. Resistance rau lub hauv paus deformation: cov khoom muaj zoo puas elongation
3. Cov nyhuv zoo: Qhov no yog qhov loj tshaj plaws ntawm cov khoom
4. Rov qab siv dua: tom qab siv, nws tuaj yeem rov qab los rau hauv lub xeev qub tsuas yog muab tso tseg.
