Canada Customs, in conjunction with other law enforcement agencies, is taking the lead in the effort to stem the flow of drugs into the country, to apprehend drug offenders, and to seize their illicitly obtained profits. While carrying out these missions, the Customs office must also ensure that the movement of legitimate goods proceeds with minimum delay and inconvenience; Canada's free trade agreement with the U.S. and the future implementation of the North American Free Trade Agreement will only add to the volume of international trade. Shipping drugs in commercial cargo, instead of through individual couriers, has become a popular method of transport among traffickers. Yet it has several drawbacks: the organizations require a "legal" infrastructure to handle the drug loads and the traffickers lose physical control over the drugs as they travel through the commercial transport system. It is at this point that Canada Customs can be most effective in its mission. The agency uses both drug detector dogs and state-of-the-art x-ray machines. To ensure that detection technology is practical and useful, there is a close working relationship between enforcement and technical personnel. One new technology being developed by Customs is the ion mobility spectrometer. The continual exchange of information on an international level also enhances the development and use of technology.