https://animalhealth.pfizer.com/sites/pahweb/us/en/Products/Pages/Solitude_IGR.aspx
An Effective Weapon in the Fight Against Flies
SOLITUDE IGR is an insect growth regulator that inhibits development of the exoskeleton in immature house and stable flies, preventing them from becoming adults.
SOLITUDE IGR is a feed through fly preventative which, when mixed 1/2 ounce into a horse's ration daily, will prevent house and stable flies in and around horses, horse barns, stables, paddocks and race tracks.