This International Standard establishes the preferred range of nominal dimensions and associated tolerances for a series of hydraulic cylinder rod and piston seal housings for reciprocating applications in the following range of dimensions: - cylinders from 16 mm to 500 mm; - rods from 6 mm to 360 mm. An additional range of seal housings is detailed in this International Standard to meet the reduced envelope requirements of the 160 bar (16 MPa)1) compact series of ISO 6020-2; these smaller section seals require stricter piston rod and cylinder bore tolerances. The range of dimensions is as follows: a) cylinders from 25 mm to 200 mm; b) rods from 12 mm to 140 mm. This International Standard does not give details of seal design, since the manner of construction of seals varies with each manufacturer. The design and material of the seal and any incorporated anti-extrusion component are determined by conditions such as temperature and pressure. This International Standard only applies to the dimensional criteria of products manufactured in conformity with this International Standard; it does not apply to their functional characteristics.