Feeder Fresh Nectar Defender is an all-natural product that protects the freshness of hummingbird nectar and stops spoilage. It is bird-safe, and works using a micronutrient naturally consumed by hummingbirds in their diet of nectar and insects. Feeder Fresh ND will protect your nectar for weeks, and hummingbirds will enjoy fresh nectar every time they visit your feeder. Simply add a small amount to your current nectar. One bottle lasts an entire season. Contains no artificial preservatives or dyes. Once you try Feeder Fresh ND, you will never want to feed hummingbirds without it. Patent pending.