Caravan damp meters

I've got the Brennenstuhl Moisture Detector MD.

Twenty quid.

It's met all my moisture detecting needs for the past five years.

Available from all good online delivery portals.

Don’t go for cheap & cheerful go for the most expensive you can afford. The damp meters for wood(tree fellers) use are accurate I’ve owned many. Stihl are a good reliable make👍🏻

the black cap is a prong guard👍🏻

Be aware that they work by inserting two prongs into the surface being tested. They leave holes.

But the holes will be filled by the dampness of the material filling and expanding.   

Not in the vinyl type wall covering ☹

so what is that attached to then I did not realise that you were aware off his outfits construction.

 If a meter with prongs does leave holes the visual impact can be reduced by rubbing a little sealant over the holes and wiping with some white spirit on a cloth.  There are meters available which do not use prongs but they are expensive and used primarily. I suspect, by the trade - my mobile engineer uses one.

Good tip, Commeyras, thanks👍🏻