Listing is for one quart bottle.
Mercury Marine gear lube outperforms automotive gear oil in marine applications because of its specialized additive package designed for marine gear cases. Continued use of this gear case lubricant will:

Provide maximum protection against excessive wear - even in the presence of water
Prevent corrosion and pitting
Help extend gear life
Mercury Premium SAE 80W90 Gear Lube is recommended for lower units for outboards below 75 horsepower.
Mercury Premium SAE 80W90 Gear Lube should not be mixed with Mercury High-Performance SAE 90 Gear Lube.