Flash & Glow Safety Light Jumbo Easy-On, Easy-Off Bright LED Safety Light 100% Silicone, High-Visibility LED Lights, Easy to Attach to Collars, Leashes, Backpacks or Clothing, etc. Water Repellent, Replaceable Batteries (Included, 2 x CR2016) Keep you and your pets safe at night, Assorted colors To activate light, open and remove small paper tab located under LED module. 3" x 1" x 1" - weight 2 oz.