Sigg 3 Stage Sports Top Replacement Part - leak-proof closure for drinking bottles. The Sigg 3 Stage Sports Top closure is the perfect replacement for all Sigg wide-mouth drinking bottles. The mouthpiece can be easily opened and closed with your mouth, making the drinking bottle a great companion for various sports activities such as cycling and jogging. Additionally, the practical screw cap ensures that the bottle is always sealed tight, guaranteeing it is leak-proof. The screw cap is, of course, BPA-free and contains no harmful substances, including phthalates or estrogen-active compounds.