The document describes the Test Pad TPD-400, a device for measuring clamping force. It is lightweight, thin, robust and portable. It is placed between the paper roll and clamp contact pad during force testing to show the real clamping force directed at the paper roll. Key specifications include a measuring range of 0.5-100 kN with 0.5 kN intervals, dimensions of 400x250x50mm for the pad and 205x205x55mm for the display unit, and weights of 7.5kg for the pad and 1.2kg for the display unit. The Test Pad can be used to test, adjust, and troubleshoot paper roll clamps and pressure selection valves.