It works!
Not sure if it's child spill proof, but it's definitely puppy spill proof! Our knucklehead loves knocking over drinks when we are not paying attention!! The lid does not allow anything in or out!! Coupled with my red solo from you guys its quite the hit!! (Purchased this one from dolphin research center)
Pirani Life
Happy to hear the Twist-on Tumbler Lids are working out great for you, Mark! We love that they're keeping your knucklehead's spills contained and that they pair so well with your red solo cup. Thank you so much for the amazing 5 star review, and we're thrilled the lids are such a hit!