HIPS is short for High Impact Polystyrene and is very similar to ABS. The primary difference is that HIPS uses Limonene as a solvent. This means that you can use HIPS as a support material which can then easily be dissolved by placing your print in Limonene. This is a fantastic alternative to sanding away regular support material. HIPS is as easy to print with as ABS but is much less likely to warp. HIPS is ideal for printing in conjunction with ABS because it has a similar strength and stiffness profile to ABS which means they complement each other well. It also helps that HIPS and ABS need to be printed around the same temperature.