Mitragyna speciosa is an evergreen tree that can grow to a height of 25 m (82 ft) tall and the trunk may grow to a 3 ft (0.91 m) diameter. The trunk is generally straight and the outer bark is smooth and grey.
Overall though, metal is a much better option than plastic. In most cases, it is much more effective and reliable, and the right choice of metal will avoid the pitfalls of rust or weakness. Aluminium, steel and stainless steel are the three metal gutter materials for guards that homeowners can choose from.
This is a material property for strength, not for stiffness or resistance to deflection. Generally speaking, 50ksi material tends to be more likely required in high-load applications (heavy floors, heavily loaded load-bearing studs, load-bearing headers). 50ksi is rarely required in curtain wall applications.