This Mobile Home Direct Vent Kit (sold separately) is for use on the 30, 40 and 50 Gal. Direct Vent Manufactured Housing Gas Water heaters. The kit includes an adjustable roof jack that adjusts 30-60 in. and a air inlet. The Direct Vent kit must be installed in accordance with the instructions furnished with the manufactured housing direct vent gas water heater. No other roof jack or air inlet assemblies are approved for installation with the manufactured housing direct vent gas water heater. Clamps and secure strapping are packed in the water heater carton.