2.2 Assembly with standardize reference fitting Prior to any testing of luer fittings, the fittings must be first assembled to a standardized reference fitting typically made of stainless steel. Examples of reference fittings of different figures used for different testing are shown in figure 2, a brief example of the internal design of a figure 5 reference fitting in 2D sketch is also shown in figure 3. Figure 2. Example of reference fittings of different figures (Enerson, n.d) Figure 3. Standardized