Ours are wooden...not nice to fall down! We have a pressure fit on the top, cant put anything fixed there as its the original stair posts - and cant put anything normal on the walls as its not square (old house!)
As it is it wriggles loose so she isn't allowed upstairs unsupervised - but when they are in a bed they can escape lol
So this is perfect and I said as soon as she is in a bed and can get out we need something better
I also HATE the gate at the top of the stairs, I fell over it (going up thank goodness) and thought I had broken my toe..its a lovely shade of black now!