KCB-55 gear pump spares mechanical seal:

China KCB-55 gear pump spares mechanical seal:

Note: because this type of oil pump has many USES, the sealing material (friction pair) is also different, in order to ensure the reliability of the seal
The manufacturer recommends the following:
 clean oil (excluding working condition of particulate matter) - ring friction pair chooses (sic), static ring friction pair chooses (graphite)
Working condition with particles and large vibration -- the dynamic ring friction pair is selected (alloy/silicon carbide), while the static ring friction pair is selected (alloy/silicon carbide).
Can also be customized according to customer requirements.If does not require the default as ( clean oil)