WELCOME TO METFAB MACHINES 

In Pyramid Design, bottom rolls rotate along fixed axis. Top roll moves up-down to bend the profile. It is economical, rugged design but results in long flat ends that need to be cut if undesirable. All 3-rolls are driven hence bending with minimal damage to surface.
Double Pinch In Double Pinch Design, both bottom rolls traverse up-down allowing curving of even ends while top roll position is fixed.  With all 3 rolls driven, jobs are rolled with minimal scratches. Ideal for bending full circles, rings. Can form  compact diameter coils