mini-Compacta US (40 litres) / U (60 litres) / U (100 litres) / UZ (150 litres): ? Impeller end: shaft seal ring ? Drive end: 1 shaft seal ring ? A grease fill is provided between the impeller-end and drive-end shaft seals. mini-Compacta US (100 litres) / UZS (150 litres) / variant C: ? Impeller end: mechanical seal ? Drive end: 1 shaft seal ring ? An oil reservoir, which is supplied filled with ecologically acceptable white oil, is fitted between the impeller-end and drive-end shaft seals.