Stock fishing or bass mid studs don't fit? This is a 15-piece stud kit for a Mercury 2.5 Liter ROS (Race Off Shore) 15" or 20" mid-section with the thicker Can. The kit includes five (5) 7/16" studs with two (2) that mount in the can and three (3) that mount in the lower unit, five (5) thick OEM spec case hardened washers, and five (5) new stainless lock nuts.