gladwell dot com / Smaller A typical insult arrives at a rate of seven millilitres a second, and might total seventy millilitres of fluid. The liner can clear that insult in less than twenty seconds. The core can hold three or more of those insults, with a chance of leakage in the single digits. The baby's skin will remain almost perfectly dry, and that is critical, because prolonged contact between the baby and the insult (in particular, ammonium hydroxide, a breakdown product of urine) is what causes diaper rash.