Oil Seal TC 42x72x5.12mm - Nitrile - ID 42mm OD 72mm 42x72x5.12 - TC Double Lip NBR Rubber Oil Seal with Garter Spring cr 41.6kN It helps hold the bearing

It helps hold the bearing in place without extra hardware

UCFC210-30 Bearing

Static load rating Cor 1130 N

designed with C4 clearance and two metal shields (ZZ)

This handy guide explains its role:

Oil Seal TC 42x72x5.12mm - Nitrile - ID 42mm OD 72mm 42x72x5.12 - TC Double Lip NBR Rubber Oil Seal with Garter Spring cr 41.6kN It helps hold the bearingTC42x72x5 12 Double Lip Rotary Shaft Seal Nitrile Rubber TC style rotary shaft seal This TC42x72x5 12 is a Rotary Shaft Seal Double Lip Shaft Diameter 42mm Width 5. 12mm For Bore Diameter 72mm Nitrile Rubber Lip Material. Item Sku : TC42x72x5. 12 Type : TC 42x72x5. 12 mm Inner : 42mm Outer : 72mm Width : 5. 12mm Size : 42mm x 72mm x 5. 12mm Seal Material : Nitrile Butadiene Rubber Temperature Range : 40 to 248 F