What is PVC?
https://www.google.ca/search?q=vi-lux+pvc+mouldings
Cellular PVC is also known as Polyvinyl Chloride or simply put- Vinyl.
"...cellular PVC is a maintenance free, rot resistance alternative requiring no priming or painting. When compared to pine, cellular PVC products outperform pine in impact strength, water absorption and resistance to burning."
"Homeowners love PVC trim because it is virtually maintenance free and it complements all exterior cladding materials, including vinyl, wood, stucco, fiber cement, and brick."
"Vinyl (PVC) material characteristics
- Maintenance-Free
- Requires no painting/finishing
- Resistant to heat loss or gain
- Resists condensation
- Waterproof – unaffected by water
- Resistant to moist, salt-laden air, pollution, airborne chemicals
- Impervious to insects
- Insulates against noise
- Flame retardant (ASTM D635-03) – will not support combustion"