Water Pump Mechanical Seal AP0650370
Fitment - RSV 98-10, Tuono 02-10, Caponord 04-07
Genuine Aprilia water pump mechanical seal, part number AP0650370, item number 13 in the diagram.
This fits within the engine behind the water pump and seals the drive shaft preventing any oil from potentially entering the cooling system.
Please also see the water pump drive shaft seal.