What is this called?

[WhatsInANameIWonder]

I was given this, and need a couple more. It’s the most successful way for my little girl to drink water.
Adding a pic here (I know it takes a little while to be presented) - what should I be searching for? Everything I’ve tried is just returning traditional milk tests. Getting v frustrated!

Did the top come with the bottle?
It says Tommee Tippee on the bottle so look on their website.

Don't know if this helps

www.johnlewis.com/tommee-tippee-closer-to-nature-bottle-to-cup-transition-sippee-trainer/p3080348?s_ppc=2dx_mixed_fashion_BAU&tmad=c&tmcampid=2&gclsrc=aw.ds&gad_source=1&gad_campaignid=20155423421&gbraid=0AAAAAD2el1yk82X8ZWRseL-oq-PV5kWPV&gclid=Cj0KCQjwxJvBBhDuARIsAGUgNfhgUAgJ6OBqqQLIYhDFbfPWU-Xlj4V0MW72bW2x1G7v9PSZGQXkhGEaAvQEEALw_wcB

I searched sippy cup teat if you want to find other brands.