Attractant refill for Rescue WHY wasp, hornet, and yellow jacket trap. Ideal for trapping paper wasps, bald-faced hornets, European hornets, and yellow jackets. Non-toxic mode of action, pesticide free. Active ingredients: (Yellow Tube) Heptyl Butyrate, (Vial) 2-Methyl-1-Butanol, (Green Tube) Acetic Acid.