If we talk about the core reels that are made by Shimano, then the aim of this brand has always been to make the reels that are lightweight, low profile bait casting reels along with being strong and durable. Basically, the core reels that are made by Shimano include the frame that is made by magnesium.
The spool of these reels is also of magnesium. The purpose of making the frame and spool with such metal is that these core reels would be light in their weight and would be much stronger and durable. These core reels are indeed light and responsive in nature but still these are durable and strong also as compared to their weight.
All of the core reels have precision ball bearings and are quite effective in their work. These reels by Shimano are surely suitable for all kinds of fishing environment. These lightweight and durable reels by Shimano aim to bring fineness and power together into one structure. These reels are quite efficient in their work and include high efficiency gearing. These core reels have 8 ARB bearings along with one ARB roller bearing. If we discuss about the gear ratio, then these have 6.2:1 gear ratio that brings in about 28 inches of line per handle turn. These reels do lessen the fatigue and are easy to use.