Features: Made from high quality carbon steel, these corner brackets are durable and solid. Surface is plated with nickel for good rust resistance and better performance. Widely used to reinforce right angle corner joints of aluminum extrusion profiles. There are total 10 pieces of brackets in one pack that you can use for many projects. EU-2020, EU-3030 and EU-4040 for your choice to connect different profiles, EU-2020 is for profiles with 6mm slot while EU-3030 and EU-4040 are for that with 8mm slot. The EU-3030 is suitable for 3040, so it is marked as 3040. Specifications: Material: Carbon steel Surface Finishing: Nickel plating Type: EU-2020, EU-3030, EU-4040 (Optional) Quantity: 10pcs Package Includes: 10 x Brackets (screws are NOT included) Note: Please note that customers need to match M6 machine screws by themselves. There may be gaps on each model, which does not mean that there is a problem with the product. It is an interface designed to connect other aluminum profiles. Please note that the new type and old type of this product will be sent randomly, and make sure you will not mind before ordering.