Below is a list of usage:
• (2) sets per Catalina 28 in mast furling rig
• (2) sets per Catalina 310 in mast furling rig
• (2) sets per Catalina 310 non furling rig
• (2) sets per Catalina 320 in mast furling rig
• (2) sets per Catalina 320 non furling rig
• (2) sets per Catalina 350 in mast furling rig
• (2) sets per Catalina 350 non furling rig
• (2) sets per Catalina 387 in mast furling rig
• (2) sets per Catalina 387 non furling rig

They are not full spreader boots but should be considered the inner layer of protection to be covered with a set of leather spreader boots for ultimate protection of your sails.

• Length (fore and aft): Approximately 2-1/2"
• Height: 1-1/4"
• Depth (athwartships): 2"
• Hole to Hole (center to center): 1"
• Hole diameter: 1/2"