All our items are manufactured from pressure treated and planed redwood timber from sustainable forests. This is now treated with new safer Osmose Protim P60, which DOES NOT contain arsenic as older treatments used to. The preservative is completely fixed within the timber and will not leach out in any environment. Pressure treated timber is fully compatible with metal fixings, such as nails and screws. This treatment provides complete protection against decay and insect attack. No maintenance is required following installation. All treated timber has a 15 year guarantee against rot and fungal decay. Timber is pleasing to the eye and matches with surrounding items, especially in rural surroundings. Because it is a natural product, every piece of timber is unique. Every piece will exhibit different growth patterns and characteristics, which we feel adds to its attraction.