Our neon 12 ounce plastic glasses look great day or night. This 4 pack of glow cups comes with 4 different and exciting colors complete with glow sticks that fit in the middle of the cup to give them a great looking glowing effect in the dark. These UV reactive plastic cups look amazing under black lights, too! Simply crack and shake the glow stick to activate and insert up the middle of the glass. Each pack of 4 comes in a great looking retail pack. While the glow will last for about 4 hours the cup is easily re-useable and can be hand washed and will still glow under black lights.