ELEGOO Standard Resin (These are 1000g or 1kg bottles) Elegoo Standard Photopolymer Resin, an inexpensive resin that works with a variety of different 3D printers and is available in a variety of different colors. The Standard Photopolymer is a fast-curing resin that is compatible with Mono LCD 3D printers like the their Mars 2 Pro. VOC free: Volatile organic compounds (VOCs) are toxic emissions that come from heated plastics. They're why you need good ventilation while 3D printing, as they can make you sick if you're not careful with your work area. Fortunately, ELEGOO has created a resin that minimizes your exposure to these dangerous fumes. However, that doesn't mean you should have good ventilation and facial protection when using ELEGOO resin. Minimal smell: ELEGOO's minimal fumes also means minimal smell while printing. That's a welcome relief from the burnt plastic stench that resins with VOCs typically give off. Methacrylate monomers: ELEGOO uses the methyl ester of methacrylic acid to enhance its adhesion strength. With each layer better gripping the previous one, you can worry less about warping and expect a more consistent surface on your finished product. Printer compatibility: ELEGOO makes its own 3D resin printer with excellent reviews, the Mars, but its resin is compatible in all UV-based 3D printers that support 3rd-party resins. That way, you more than likely don't have to buy a whole new setup if you just want to give ELEGOO's resin a test run.