Bio-mechanical properties equivalent to Initalloy small diameter archwires. Bio Active Form A lets you begin treatment with large diameter .020 x .020 or .018 x .018 archwire and active third order bends. The biomechanical properties ( force, super elasticity and shape ,memory) are equivalent to small diameter archwires such as Initialloy .014 ( 50gm) on incisors , Initialloy .018 ( 150g) on premolars and Initalloy .020 ( 250g) on molars.