When we were designing our original Ion8 bottles, we wanted to make sure they were leakproof, so we ensured lids were reliably and securely tight, firm enough to form and maintain a good seal. We found some users had difficulty removing the lids after use, so we developed a new design with a soft grip within the lid. 

Users loved it and appreciated this thoughtful feature. 

But we are always trying to improve...

This year, we improved them further still, with a diamond textured grip. This diamond grip has a higher surface area and pronounced peaks that improve grip traction by over 100% at the same strength level. 

OK. It's not just easier for girls. It's easier for everyone! But that would have made a much less interesting title on the article. :)