TYPE SSI-16 : is Inherently unbalanced metal bellow seal. This seals are independent of direction of rotation. The unique feature of this type of seal is that, there is no dynamic ‘O’ rings and therefore it will never hangup or damage the shaft and sleeve, it also has an ability to handle corrosive as well as abrasive & viscous media. These seals have self-cleaning & non-clogging cons... https://www.samsealsindia.in/metal-bellow-seal.htm