PLA is a sturdy, plant-based material that is great for sticking to the paper, glass, cloth, and metal surfaces. With a glossy finish, PLA is the preferred material by most expert Doodlers. PLA is non-toxic, BPA-free, recyclable, and compostable in industrial composters. Also compatible with the 3Doodler PRO+. NOT COMPATIBLE WITH THE 3DOODLER START OR 3D BUILD & PLAY