The conventional method for lifting Gridiron manhole covers is by the application of a plastic knob with a metal screw inserted in the base of the manhole.
This type of removal of the manhole cover is certainly the best known and recommended, particularly in cases where it is only occasionally lifted.
Gridiron has further simplified the operation: we have offset the lifting knob which means that the manhole cover can be lifted and moved easily, reducing effort to the minimum.

1) Conical plastic knob with screw in galvanised steel, stainless steel and/or brass.

2) Section of the manhole H = 50 or H = 85 with conventional lifting.
Knob in offset position to facilitate inspecting.