Chevron Rando HDZ 15 is a premium mineral based lubricant that is used in Hydraulic Systems. Rando is a line of Chevron Lubricants that covers a variety of hydraulic applications. The "HDZ" series is a group of premium Anti-Wear (AW) hydraulic oils with outstanding oxidation resistance. In addition, the "Z" signifies that this product has a High Viscosity Index (HVI) which means it has great flow properties in extreme temperature conditions. 15 represents the thickness of the oil which is an International Standards Organization Viscosity Grade (ISO VG) 15.
This line of hydraulic fluid was originally called Texaco Rando HDZ until Chevron acquired Texaco in the year 2000.