Hood LH-40B for Olympus 45mm F 1.8 ?

Hello,

Would like to know how this hood is fixed on the lens since this metal lens has no slot to hold it firmly.

If you have to use the thread to screw the hood on, how do you fix a  filter chen the hood is on.

My concern is to make sure the hood will ber secured as well as on plastic lenses which have a slot to fasten the hood.

Is there a finish (or quality)   difference between original hood made by Olympus and copies made by other manufacturers.

Thank you and Happy New Year .

Sincerely,

Bernard