Silicon Nitride Ring is the winner when it comes to its ability to take the heat and abrasion dished out by extreme saltwater conditions and long runs with tight drags. Since SiN was originally as a ball bearing material in jet engines it can handle just about anything and is perfect for Wire Line trolling. The SiN rings are slightly heavier and larger in diameter than other rings to maintain the rugged specifications that makes Fuji Guides with SiN rings the perfect choice for heavy duty boat or offshore rods.