This is an aftermarket Piston 369-00001-0 with Piston Ring 351-00011-0 for Tohatsu /Mercury outboard engines.
Item Description:
Piston Kit std (55mm) for Tohatsu Outboard Motor
4HP-5HP 2-Stroke
Mercury-Mariner
4HP-5HP 2-Stroke

(Kit includes Piston, Rings, Wrist Pin, & Clips)
Piston Diameter: 55.00mm

Piston Height: 54mm

Wrist Pin: 14mm

Part No BHB369-00001-0
R.O: 369-00001-0, 779-9615