Most duty belts have a width of 2-1/4 inches and are either made of ballistic nylon or leather. Many Canadian police departments have had officers complain of having back pain due to their supposedly rigid leather belts. In response, many Canadian departments are now switching to nylon belts because they are considered by some to be more flexible. The Service de Police de la Ville de Montréal (SPVM), the second largest municipal police service in Canada, gave a contract to a consulting firm in order to find more ergonomic solutions.