LEFF Amsterdam Watch Tube T40 LT75713. For the design of the Tube watch LEFF Amsterdam teamed up with Dutch Designer Piet Hein Eek. Piets unparalleled vision on design and LEFF amsterdams raw, industrial and sophisticated approach, came together in an amazing collection of refined yet tough watches. The design of the Tube watch has an iconic ring that functions as the clocks face. Therefore, you can recognize every LEFF amsterdam watch by this unique characteristic.