The three larger ones are true Speed-Ezel's.
The paper slides in from the ends and is held down by 1/4" wide flanges.
They are classic high production, fixed size units that will last a lifetime.
The two smaller ones are (probably) Saunders brand easels.
The black 1/4" square solid steel hinged frame is heavy enough to hold down even the most curled paper.
They are also timeless and fool-proof fixed size easels.