A mechanical seal has an axially floating seal face (21) in sliding contact with an axially stationary seal face (22). A biasing means (33), such as a magnet, biases the floating seal face towards the stationary seal face. The axially floating seal face and the biasing means are rotationally fixed relative to each other and the axially stationary seal face is free to rotate relative to the axially floating seal face. The seal may be used, for instance, as a bearing protector or isolator.