Airtite Systems sells the only adhesive backed Double switch sealers on the market today! Don"t be fooled...sealers without adhesive leak air! The kit contains 4 adhesive backed Double switch sealers. When you cut two switch sealers to make a double switch sealer it will leak air! You"ve felt that cold air in the winter or hot air in the summer at the outlet opening?? That DRAFT is costing you money and making you uncomfortable. STOP your money from going out the window. All sealers are flame retardant and super easy to install.