Zero In Flea Killer Refill Pack. Contains 2 x replacement bulbs and 3 x replacement discs. Poison-free - kills fleas with no sprays. Refills for use with Zero In# Flea Killer unit. A safe and effective way to rid your home of fleas without using poison sprays.Contains 3 refill discs and 2 spare lamps for use with Flea Killer (ZER020).7-Watt lamp rated for 1,000 hours continuous use.Recommended to replace sticky discs every 2-4 weeks.