Lighten your load and drink right from the source. We took our go-to flask and added filtration to create a system that delivers hydration without contamination. The filter — light and compact — screws on top so you can drink right from the flask. Or — if you’re carrying more water — use the system to fill a bottle or reservoir. Care: Avoid freezing filter. Freezing may ruin the hollow fiber membrane. If in freezing conditions we recommend you keep the filter in your pocket or near your body to prevent freezing. *Effectively removes common waterborne bacteria, such as E.coli (99.999%) and parasitic cysts (99.9999%) per HSF 42. Included in the package: - UltraFlask+ 500ml Flask - 42MM Filter Flask Cap - Bite Valve - BackFlush Adapter - Filter Manual - Basic Care & Use Instructions Specifications: - Capacity: 500 mL / 17 fl oz - Weight: 65 g / 2.3 oz - Dimensions: 240 mm x 70 mm / 9.4 in x 2.8 in - Material:TPU, Silicone POM, Hollow Fiber, ABS