Choose environmental protection to save can the twilight of train in excess specified length give out light material, absolutely do not have poison without any radioactivity , is harmless , free from contamination, for human body, it is absolutely safe. Mix in transparent resin arts and crafts among, need to absorb and store various evidently natural lights only 10-30 minute after , convenient but in night or dark place can can last for a long time selfluminous. In daytime shallow white colour and night convenient nature send out ( the smooth or yellow green light of sky blue ). It inhales light - save can - - the course of giving out light but infinite recursion, use permanently.