These bite valves are great for older kids and adults. I used mine all the time before having children. Once I was sharing my valve with a teething toddler, I started to have problems. The kid would pierce them withing a second of starting to drink and then leaking was an issue. Bite valves were literally destroyed within seconds of their first use. I had to switch to a sturdier water bottle. I plan to go back to a bite valve system once the kid is carrying his own water.