High impact polystyrene, or HIPS, is a material blend of polystyrene and rubber. Because it dissolves in limonene solution, it’s often used for support material, eliminating the need for removal via abrasives, cutting tools, or any other such things that leave your print less-than-perfect.
HIPS is very similar to ABS, in fact, it’s actually stronger. As such, apart from being used as a support material, it is also very capable and useful as its own material. HIPS is easily painted, machineable, and works with a large number of adhesives. It’s also food-safe, non-toxic, fully recyclable, and non-hygroscopic, meaning it won’t degrade in humid environments.