Usage:1 same usage as rolling swivel， stablize hooks to prevent fish escaping.2 more flexibility， can be individually tied to hook， can also pass through fishing line， strengthen overall balance and stability.3 lightweight and wear-resistant gadget， belongs to consumable， you can buy in large quantities， there are a variety of sizes for options.4 different sizes for different fishes.Color: Silver Black.Material: Metal.Model: 2 #.Dimensions (L x W): about 20 x 18mm.Rod length: about 20mm.Ring inner diameter: about 3.40 ¡À 0.05mm.Rod inner diameter: about 1.60 ¡À 0.02mm.Rod outer diameter: about 2.85 ¡À 0.01mm.Package included:100 x 2# dropline swivel.