Providing extra saftety this "push-and-twist" cap is compatible with MSR liquid fuel bottles manufactured after 1981.
Prop 65 N (Diisononyl phthalate): This product can expose you to diisononyl phthalate, which is known to the State of California to cause cancer.
https://mtn-sports.myshopify.com/pages/prop-65-frequently-asked-questions