Piston head sealing X-RING (XRTP) with quadrilobate section, during dynamic stresses are not subject to rounding in the seat. X-Rings have less wear than O-Rings as they require less radial pre-compression which results in less contact pressure.A lubricant reservoir can be generated between the sealing lips.There is an optimization of the sealing effect thanks to a better distribution of the pressure due to the square section.X-Rings eliminate any negative effects due to the mold closing line, since this is located in the groove between the two lips.
