Features: brand new and high quality UV Color Changing Embroidery Machine Thread: The thread will keep the changed colors as long as they are exposed to UV light. But when no UV light, the colors will return to their original colors after a few minutes. There are 19 colors available, the colors will change to specified colors under UV light as shown on the picture. Wide Applications: 30WT (150D/2) strong thread can be widely used for machine embroidery, quilting, piecing, machine sewing, fine hand embroidery etc. Skin-friendly Material: High-quality polyester material is skin-friendly! How to Get the Best Color Changing Effect: 1. put the thread in the for stronger UV light, the better color changing effect you will have. 2. Usually a project with denser stitches or multiple outline stitches will have more visible color changing effect. 3. Lubricating the thread only with a non-staining silicone spray or sewers aid. Instructions: 1.We suggest to use large eye needle to reduce friction. decolorant and steam ironing the thread is not recommended. Dry ironing is allowable, but Maximum Temperature should be no higher than 176° F. 3.Washing the thread is allowable, but make sure that the Water Temperature should be not higher than 104° F. Specifications: Material: Polyester Color: As Pictures Show Styles: 1/2/3/4/5/6/7/8/9/10/11/12/13/14/15/16/17/18/19 Size: Approx.6.3x13cm/2.48x5.12in Weight: Approx.100g Package Includes: 1 Spool Color Changing Sewing Thread (19 Options) note: 1.Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you bid. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you!