The Hand Pump is an excellent dual action pump used to inflate all Tumbl Trak air products with proper attachments. The product delivers a continuous stream of air in both up and down strokes. The release valve is turned counter-clockwise to pump air in down-stroke when inflatable is full and there is no back pressure. This pump is very effective for topping off large units. Size - 8.56" wide x 18.75" long x 4.5" high. Peak Pressure - 14 psi. Weight - 3 lb