Lure Module is one of two items that attract Pokemon when used. Unlike the Incense item, the Lure Module must be applied to a Poké Stop. This means that other trainers in the area can benefit from the item. Once activated a Poké Stop will emit pink flakes falling from the Poké Stop to show an active Lure Module.
These can be purchased in 1 and 8 increments from the Shop.