Concave Former Kit for Multi-Bend tube bender
22mm Concave Former
22mm Concave Roller 
Top plate and spacer
To suit Multi-Bend tube bender
Picture showing showing bends - from the Top
Mild steel  (20mb) 26.9x2.3mm
Aluminium 25mmx1.5mm
Stainless 22.5x1.6mm