①. These insert nuts are made from zinc plated carbon steel for durability and rust protection. ②. Screw-in insert nuts have an external thread and hex socket drive and are screwed in with a hex key wrench. ③. Insert nuts are advantageous over barrel nuts and T-nuts, because they can be installed from one side of the workpiece. ④. There are screw-in insert nuts in different sizes and take different screw sizes that you can choose for your project. ⑤. The pre-drilled hole must be as deep as the length of the insert nut plus any portion of the bolt that may be screwed past the end of the nut in the work piece. ⑥. An insert nut provides a threaded socket for a wooden workpiece, similar to a wall anchor. These insert nuts are inserted into a pre-drilled hole by screw in, in that case the external protrusions bite into the wood, preventing the nut from either turning or pulling out. ⑦. Features: These insert nuts are made from zinc plated carbon steel for durability and rust protection; Screw-in insert nuts have an external thread and hex socket drive and are screwed in with a hex key wrench; Insert nuts are advantageous over barrel nuts and T-nuts, because they can be installed from one side of the workpiece; There are screw-in insert nuts in different sizes and take different screw sizes that you can choose for your project; The pre-drilled hole must be as deep as the length of the insert nut plus any portion of the bolt that may be screwed past the end of the nut in the work piece. ⑧. Specifications: Material: Zinc plated carbon steel; Type: Hex socket screw-in; Thread Type (pitch): Coarse thread. ⑨. Size and Quantity (Optional): M6*10mm 20pcs; M6*13mm 20pcs; M6*15mm 20pcs; M6*17mm 20pcs; M6*20mm 20pcs; M6*25mm 20pcs; M8*13mm 20pcs; M8*15mm 20pcs; M8*17mm 20pcs; M8*20mm 20pcs; M8*25mm 20pcs; M10*25mm 20pcs. ⑩. Package Includes: 20pcs x Insert Nuts. ⑪. Note: 1. Please allow 1-3 mm error due to manual measurement and 1-3g weight error make sure you don't mind before ordering. 2. Due to the lighting of the photos and the difference of monitors, the pictures may not reflect the actual color of the real item. Please make sure you don't mind before ordering, thank you! ⑫. About Shipping: 1. Please pay attention to your delivery address such as: name, street, house number, doorbell/email without name, etc. is correct, or the order will not be delivered correctly. 2. All items will be shipped within 3 business days after the payment is received. Most times you will receive them within 8-12 days then. The specific delivery time is depend on circumstances. 3. During the shopping process, if you have any questions, please feel free to consult us, we will reply you within 24 hours. ⑬. Hope you have a pleasant shopping experience!