Potting boxes are moulds used to house an electronic assembly along with an insulating material, which then protects the assembly from shocks and vibrations. Examples of components that might be protected this way are sensors, LED lights and capacitors. Potting is the process of filling the electronic assembly with a gelatinous substance, which then hardens to fit the mould it is placed in.
The electronic assembly is placed in the potting box, or mould, which is then filled with the chosen insulating material. This gelatinous substance then hardens and sets around the electronic assembly. Not only does this prevent against vibrations and shocks, it also prevents the electronic assembly from being damaged by moisture or other corrosive agents.
Potting boxes generally vary by size and shape, depending on the dimensions of the electrical assembly that you want to house in them. The material used to fill the potting box can also differ. Usually silicone rubber gels are used, but thermosetting plastics are also an option.