Basically a press welded grating, it is strengthened by round bars welded beneath the twisted cross bars and in the same direction as the bearing bars. See the photo to the right.

Mesh spacing:
30 x 19 mm with round bar welded on beneath so that a test ball 15 mm in diameter cannot fall through.

Bearing bar measurement:
20 x 3 mm up to 60 x 5 mm