Near the end of the episode when Ben, Chin and Steve are in McGarrett's office, they speak to each other using a fake a "script", expecting to be heard by the person bugging the office. At one point a reel-to-reel tape recorder is shown, with a piece of green tape over the manufacturer's name. All that is visible is "3300"; what is being covered up is the brand name TEAC. The full name of this recorder is "TEAC A-3300", a recorder from 1972.