A decent set of bottles for the 3.5 euros I paid for them. However, while they have the appropriate shape to be stacked, they are not sturdy enough to withstand the weight on top. I bought 6 and stacked them in 2 sets vertically. In both sets, the bottom bottles cracked and opened, luckily with minor leaks, and I avoided a major flood. This happened within 1 month, so they cannot handle much weight and therefore can only be stacked empty or maybe up to 2 bottles. Definitely not 3.

It is sturdy and easily stackable. The only negative is that it does not have a second lid (an extra hole for air to enter as the water comes out). However, for its price, it is very good.