Winstory 10x Outdoor Aluminum Tent Rings Cord Rope Tensioners for Camping Hiking Backpacking Picnic Shelter Shade Canopy Round Ideal for camping,hiking,backpacking,picnic, shelter shade canopy outdoor activity Help to lock the cord and prevent it skids away Aluminum Tent Rings Cord Tensioners for Camping Hiking Backpacking Picnic Shelter Shade Canopy Material: Aluminum Size: About Diameter: 20mm; Diameter of the Hole: 4mm