Yanmar Saildrive Drain Plug for SD50 and SD40 Yanmar Saildrives.
This part is the drain plug that should be replaced if damaged when changing the oil on an SD40 or SD50 Saildrive.
The drain plug o-ring for SD40 and SD50 Saildrives is part number 189010-01130.
For Yanmar Saildrives:
SD40, SD50
Yanmar Part Number: 196326-02420