Stretches to fit gate opening up to 20 ft. Retracts to keep gate off ground when open. Electrified when closed, neutral when open. Highly visible and effective. Expando gate assembly consists of one Rub'R gate handle, one large galvanized spring, two pinlock style wood post insulators with galvanized nails, two pinlock style T-post insulators, one anchor/activator, one fence line clamp/tap and complete schematic instructions. Equipped to fit wood post or T-post openings.