The "hook and pull" technique always ... is ± 3/4 inch from the specified location. For slab thicknesses 12 inches or less, the concrete cover tolerance is - 3/8 inch measured perpendicular ...

The patented ‘no-gap lid’ manufactured by high-tech reinforced concrete products ... lid seated in a precast slab for new valves chambers and a no-gap lid in a cover slab for existing valves.