Features：
1.Wood threaded inserts are insert nuts that are inserted into pre-drilled holes in wood with internal threads
2.Threaded Inserts are best for composite materials, wood and plywood, you just need to drill a hole that the size of the body into the wood for the threaded insert.

Notes:
In softer woods, the external thread cuts easily into the wood, simply drill a properly sized hole for the body of the insert (8.5 mm, 9 mm, 9.5 mm, 3/8 inch drill bit) and screw the insert into place.
In very hard woods (e.g., white oak or maple), drill a hole close to the diameter of the male threads (3/8 inch, 9.5 mm, 10 mm bit) and screw the insert into place. If the drill hole is too small for the threads, screwing in may split the wood or the insert. If you are unsure of the wood material for your harness, drill an appropriately sized hole to test before installation.
Specifications:

Size: 1/4 inch -20 x 15 mm
Material: carbon steel
Surface treatment: zinc plating

Package include:
100 pcs * 1/4 inch -20 x 15 mm screws
2 * 6 mm Hexagonal Wrench