The results of this study demonstrate notable differ- ences among production lots of the same wire type from the same manufacturer. In addition, significant differences were found between manufacturers in certain wire types. It appeared that certain archwires made by Ormco had greater interlot variabilities in tran- sition temperature and force delivery values. This was true for 0.016-in (Af, 27 C), 0.016-in (Af, 35 C), and 0.016 3 0.022-in (Af, 35 C) archwires. A cursory visual inspection of the DSC graphs (Fig 4) and the load vs deflection graphs (Fig 5) also highlights the differences among the same wire types from various lots from the 2 manufacturers. On the DSC graphs, the slopes of enthalpy and peak heights for each wire of the same type and maker but from different lots are notably not parallel for the Ormco wires. This indicates variations in martensite start, martensite finish, As, and Af from lot to lot. Regarding RMO wires, the slopes of enthalpy and peak heights from the DSC tests demon- strated that most wires in every category had near parallel slopes of similar heights, indicating greater con- sistency in the transition temperature ranges for each wire in every lot. Similar observations can be made when looking at the overlaid graphs of load vs deflection.