These are sturdy and reliable nuts that can be used for various projects that require fastening or joining metal parts. They are made of iron, which is a strong and durable material that can withstand high temperatures and pressures. They have a square shape, which means they have four flat sides that can be gripped by a wrench or a spanner. The thread size is M8, which means the diameter of the nut is 8mm. The nuts are compatible with M8 bolts or screws of the same thread pitch. The pack contains 50 nuts, which are conveniently stored in a resealable bag. These nuts are ideal for building or repairing furniture, machines, vehicles, or other items that require a secure and tight connection.