Sensory Library › 6-Pack Colorful Hourglass Timer with Droplet Movement Image 1 of 1 6-Pack Colorful Hourglass Timer with Droplet Movement $0.00 6-pack of water and oil liquid motion tubes with vibrant, flowing colors that move with time and gravity. Add To Cart Added! 6-pack of water and oil liquid motion tubes with vibrant, flowing colors that move with time and gravity.