"Very effective bottle cooler!" star star star star star We find that double wall coolers only work when the bottle is pre-chilled. A bucket full of ice works well but is messy and we don't remember to freeze enough ice. This ice mould we leave in the freezer and we have an ice block ready made when entertaining. It really does chill a bottle of bubbly in minutes and keeps the drink cold for ages. We managed to cool and serve 4 bottles over the course of a dinner party and it impresses our guests, especially when we freeze fruit or flowers inside as a decoration. Even works outside in sunshine and then you throw out the melted water in the tray.