The Adam clasp is typically made from 0.7 mm stainless steel wire because this thickness offers an optimal balance between flexibility and rigidity. It must be rigid enough to provide proper retention by engaging undercuts on molars and premolars without permanent deformation. A thinner wire (0.5 mm or less) lacks sufficient strength and may bend or fail under stress, while thicker wire (>0.7 mm) can be too rigid, making it difficult to adapt and causing patient discomfort. Therefore, 0.7 mm wire is ideal for achieving effective retention and patient comfort in removable prosthodontics.

Reference: Craig's Restorative Dental Materials, 13th Edition.