The Sigg Explorer bottles are a range of wide mouthed, single walled stainless steel bottles. they are available in three sizes 0.55L, 0.75L and 1.0 Litre. Although they are lightweight (175g, 200g and 275g) they are very durable and should give years of service. The Stainless steel manufacturing process does not use *BPA. The wide mouth makes for easier cleaning or filling from a mountain burn.
*BPA stands for Bisphenol-A, an estrogen-imitating chemical used in the production of reusable plastic products, such as bottles, toddler sippy cups and plastics you might use for storing leftover food.