The Simpson A21Z angle is a multi-purpose angle used to create solid 90 degree angles. Using screws and nails alone can be difficult to get straight and don't create as strong of a connection. The Simpson A21Z can save you time and frustration by making it easy to get the perfect angle. Whether you're building a dog house, garage storage or shelving units, these heavy duty 18 gauge steel angles will hold up to create a strong and reliable connection that lasts. The ZMAX finish on this angle will work with treated lumber and is also suitable for normal outdoor applications.