This new style of hot cocoa bomb mold uses 3 parts (a top mold, a liner, and a bottom mold) for perfectly round half spheres every time. This is a nice large size, 70mm/2.75".
A great alternative to silicone molds for beginners, these make lovely rounds every time. They shells will be sturdy and have nice thick edges to adhere together but take up more room, time, and can make a very thick shell that doesn't like to melt very well.
Remember 3 cavities will only make 1.5 cocoa bombs, so you'll want at least 2 molds.