A piston for a pump and a pump are provided. A piston bladder (2) of the piston is cylindrical in shape, a chamber (20) is a cylindrical chamber, the chamber (20) has as inner diameter of 9.2±0.5 mm, the chamber (20) has a depth of 3.8±0.5 mm, the piston bladder (2) has a wall with a thickness of 0.5±0.3 mm, and the piston bladder (2) has an outer circumferential surface, a part of the outer circumferential surface connected to a base plate (1) protrudes outwards radially to form a protective sleeve (21).