| 摘要 |
A marker is provided for marking the location of features beneath a plaster covering. The marker has an indicator arrangement which is activated by moisture from the plaster covering to provide an indication which is visible from the exposed face of the plaster covering. This may be by swelling or shrinkage, releasing a dye or ink, pushing a pin through the plaster or in other ways including release of a spring biasing an indicator member outwards. The indicator may be held in a cup or holder and covered with a layer which dissolves when plastered over. The cup or holder may be held in place on a substrate by adhesive, a screw thread, grips spikes or ribs. |
