These bulk pin backs are made of nickel-plated copper, durable and rust-resistant. They feature a smooth surface and secure locking mechanism to firmly hold your pins in place, providing a reliable replacement for torn screws or wrench locking systems. Keep your items secure during important events. No more lost pins—this handy set ensures your pins stay locked and secure. Pre-set small screw included for easy use. No additional small parts to handle. How to use: Insert the black screw into the center hole, then use a small wrench to partially tighten the screw to secure it. Attach the brooch or medal to be fixed through the two side holes, then gradually tighten the black screw with a wrench to ensure a firm hold. Item Type: Pin Keepers Material: Brass Color: Silver Type: A/B (Optional) Size: - A Small: 6x5mm - B Large: 6x9mm For more details, please refer to the photo. Quantity: 10 Sets Note: Size measurements are taken manually and may have a 0–3mm variation, which is considered normal. Due to differences in monitor displays, the actual color of the item may vary slightly from the image. Package includes: 10 Sets x Pin Safe Locks