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.
Concerns have been raised about the ethical acceptability and food safety of Vark, as not all of it is pure silver (sometimes aluminium is used, which is toxic), nor hygienically prepared, and the foil nowadays commonly is beaten between layers of ox-gut because it is easier to separate the silver leaf from animal tissue than to separate it from paper.