Prod. (I) comprises esters of (a) hexahydrobenzoic acid (HBA) and opt. other 6-20C (cyclo)aliphatic carboxylic acids with (b) at least one polyol (II) of formula RCH2OH (where R is a straight- or branched-chain aliphatic gp. contg. at least one OH gp. and opt. one or more ether O atoms). The av. no. of moles of acid(s) other than HBA per mole of (II) is 0-2. (I) are useful as base oils (or components thereof) for formulating lubricants, hydraulic fluids, oil emulsions, heat-transfer fluids etc. (esp. EP lubricants). They have good viscosity and stability properties.