The SIGG double seal bottle top features a leak-proof spout and dust cap that protects from dirt. Thanks to its simple design -- half a turn to open or close -- it is easy for children to use.This top is one of the few leak-proof sports/sippy spout tops made for metal bottles. These caps are also great for adults looking for an alternative to the standard sports cap. SIGG Kids dust caps come in a variety of fun colors. The Glow in the Dark dust cap uses a technique that requires very little light and glows very bright. Kids love "em! Top fits all SIGG Reusable Bottles and dust caps fit hinged SIGG kids tops!