As part of the program to design low-cost products, target costs were set assuming aggressive cost reduction and high quality levels. A target cost system existed prior to 1987, but it was not considered effective. As part of the three-year program to reduce costs, the target cost system was improved and more attention was paid to achieving the targets. Aggressive cost reduction was achieved by applying three rationalization objectives. First, the number of parts in each unit was targeted for reduction. For example, the shutter unit for one class of compact camera was reduced from 105 to 56 pieces, a 47% reduction that led to a 58% decrease in production costs. Second, expensive, labor-intensive, and mechanical adjustment processes were eliminated wherever possible. Finally, metal and glass components were replaced with cheaper plastic ones. For instance, replacing metal components that required milling in an SLR body with plastic ones that could be molded reduced the SLR body costs by 28%. Similarly, replacing three of the glass elements with plastic ones in an eight-element compact camera lens reduced the lens cost by 29%.