Infused with essential oils. Refill lasts 30 days. Spring's here! Lilac Spring PlugIns Scented Gel captures the freshness of lilacs, any time of the year. PlugIns Scented Gel imparts a gentle freshness that's perfect for smaller rooms. Use only Glade PlugIns Scented Gel refills in Glade PlugIns Scented Gel air fresheners.