57 x 40mm thermal till rolls are small, paper rolls that are commonly used in electronic cash registers and thermal printers. 

They are coated with a special material that is sensitive to heat, allowing the printers to produce high-quality, clear text and images. 

The "3REE LABELS" brand is a popular manufacturer of these thermal till rolls, offering products that are compatible with a wide range of point-of-sale (POS) devices and provide reliable performance.