Tool-Free Bike Chain Link Installation SystemUser-friendly bicycle missing links feature snap-lock mechanism allowing 3-second chain assembly/disassembly. Reusable bike chain connector links eliminate specialized tools - simply align, click, and ride with confidenceCompatible with: because 11 speed chain of bike width is 5.5 mm, so this missing link chain is compatible to all 11 speed chainComplete Bicycle Chain Maintenance KitIncludes 8pieces (4 pairs) professional-grade bike chain links in compact storage case. Organized packaging prevents loss while cycling, keeping essential bicycle chain link repair components accessible during trailside emergenciesMilitary-Grade Stainless Steel Bike Chain Connector LinkForged from corrosion-resistant stainless steel, these bicycle chain links withstand extreme riding conditions. Reinforced pin joints prevent deformation during high-torque pedaling, delivering long-lasting bicycle chain link repair performanceSize: each missing chain link size is 20 x 5.5 x 7 mm; The bike chain link is 20 mm in length, 5.5 mm in width and 7 mm in height;