Chelsea Online

These envelopes are made of highly durable Tyvek fibre from DuPont, an exceptionally strong material that's difficult to tear and is also impermeable to water, keeping contents dry and safe even in extreme conditions. Because it's lightweight, you can save on postage compared to other packaging materials. These envelopes feature a clear window that allows you to display addresses with ease, saving you the cost and bother of making labels. Extra strong envelopes with address window and peel & seal flap Highly durable Tyvek construction: tear-, burst- and water-resistant Recyclable and Carbon Trust certified Extremely lightweight: saves on postage Size: C4 (229x324mm) Clear window for view of addresses Supplied in a pack of 100