Single balanced seal with reinforced sleeve and fixed bushing. Single cartridge seal with double hydraulic balancing, multiple springs outside the process and fixed containment bushing for low pressure vapour quench. Ideal for fluids that tend to crystallise on the atmosphere side and which require steam washing. Simple installation thanks to the new Fluistrip positioning device and the flange slots which adapt to different stuffing boxes. The reinforced sleeve tolerates higher shaft run-out and adapts to mixers, dryers or mills and also to assembly directly onto the pump shaft.