The Sigg Closure Screw Top is the perfect replacement for all Sigg narrow-neck drinking bottles or WMB bottles with an adapter. The practical screw cap ensures a tight seal at all times, making the drinking bottle leak-proof. Thanks to the special design of the bottle cap, the drinking bottle can also be easily held and carried with just one finger – ideal for on the go. The screw cap is, of course, BPA-free and contains no harmful substances, including phthalates or estrogen-active substances.