Premium Quality Silicon Rubber Balls for Training Purposes. These rubber balls are designed to be used at night or in winter because they contain fluorescence which gives a special effect and amazing experience. The balls should stay for a short time under the light (for example under flash light from the smartphone). After that, as soon as you bring them into the dark, their unique blue florescent color starts to glow. Wonderful effects on playing paintball or home training. Great shooting experience thanks to the high quality materials used in the production. Eventough they are softer than other rubber balls in our store, these balls have also very strong effects: They can be used for home and self defense too. Article Details: Premium Quality Rubber Silicon Balls in 50 cal. (each weighs ca. 1,3 gr.) Unique Experience: The balls glow in the dark thanks to its blue fluorescence pigment. Suitable for Paintball and Self Defense Guns in 50 caliber. Made in EU Standards: High-quality materials and engineering technics are used in the production. These balls offer special training and shooting experience. They are also ideal for slingshots.