UBMOM straw cup includes Backflow Prevention Disk to prevent the liquid in the bottle being backflow by pressure / temperature difference (hot/cold drink), while the Smart Cap is easy opening and at the same time can also help preventing water leakage for moving. Also, UBMOM straw cup can be used as a feeding bottle by replacing the straw nipple with the bottle nipple.
I’ve thrown away others since we used it. No leak at all! My son loves it! Only one thing, the cap is a little too tight, he can’t open by himself but as it doesn’t leak at all, l just leave the bottle open.