The Waterbobble, co-designed by Karim Rashid, is a reusable H2O bottle. The filter only needs to be changed every 2 months or 40 gallons (150 liters). According to those calculations, that means one bobble filter is worth about 300 bottles of water.   From the Designer | “Bobble’s ingenious design removes chlorine and organic contaminants from municipal tap water. In doing so, bobble replicates the experience of drinking crisp, clean portable water without incurring the significant costs — environmental and monetary — associate with plastic water bottles.”