For the Ultimate Sensation: Insert the vibrating bullet into the hole on the bottom of the sleeve.Dimensions:Item Length: 7.25 in.Item Width: 2.75 in.Item Height: 7.25 in.Item Depth: 2.75 in.Item Inner Diameter: 1.5 in.Insertable Length: 5.5 in. Item Package Depth: 7.25 in.Item Package Width: 2.75 in. Item Package Height: 2.75 in.