The Engineer's Ring is a ring worn by members of the United States Order of the Engineer, a fellowship of engineers who must be a certified Professional Engineer or graduated from an accredited engineering program (or be within one academic year of graduation to participate).  The ring is usually a stainless steel band worn on the little finger of the dominant hand. This is so that it makes contact with all work done by the engineer. Rings used to be cast in iron in the most unattractive and simple form to show the nature of work. The ring is symbolic of the oath taken by the wearer, and symbolizes the unity of the profession in its goal of benefitting mankind. The stainless steel from which the ring is made depicts the strength of the profession. 
Based upon the original Canadian Iron Ring ceremony, engineers receive the ring after taking an oath known as The Obligation of The Engineer, during a ring ceremony. Only those who have met the high standards of professional engineering training or experience are able to accept the Obligation, which is voluntarily received for life. This commitment is not a trivial act but is rather like the wedding of the engineer with the best tenets of their profession.
The Obligation of The Engineer
The required oath, taken immediately before accepting the Engineer's Ring, is known as "The Obligation of the Engineer" and is as follows:
I am an Engineer.
In my profession I solve practical problems. To it I owe solemn obligations.
Since the Stone Age, Human Progress has been spurred by the Engineering Genius. Engineers have made usable Nature's vast resources of Materials and Energy for Humanity's Benefit.
Engineers have vitalized and turned to practical use the Principles of Science and the Means of Technology. Were it not for this heritage of accumulated experiences, my efforts would be feeble.
As an engineer, I, (full name), pledge to practice Integrity and Fair Dealing, Tolerance, and Respect, and to uphold devotion to the standards and dignity of my profession, conscious always that my skill carries with it the obligation to serve humanity by making best use of the Earth's precious wealth.
As an engineer, I shall participate in none but honest enterprises. When needed, my skill and knowledge shall be given without reservation for the public good. In the performance of duty, and in fidelity to my profession, I shall give the utmost.
- Engineering ethics
- Iron Ring for the Canadian practice
- National Society of Professional Engineers