A Watermark Detector can increase the value of your stamp collection. Watermark 'varieties' have changed the values of some stamps from a few pence to hundreds or even thousands of pounds. Not surprisingly there is increasing interest in watermarks. A Great Britain definitive stamp (SG606), on an envelope, was sold at auction by one of our customers for £2300. Why so much? It had the 'wrong' watermark – a St Edwards Crown instead of a Multiple Crown. The same customer found the identical watermark error on a block of mint stamps and sold these for several hundred pounds each.

The stamps of most countries have at some time been watermarked.  Some watermarks are clearly visible but in most cases you will not be able to identify them without a watermark detector. The paper is thinner in the area of the watermark; with a watermark detector this area appears darker against the lighter background of the stamp paper.

The Inst-a-tector is our best selling watermark detector, used by dealers and collectors for the rapid checking of stamps. It is efficient for general worldwide use. Stamps can be mint or used. This watermark detector can be used for single stamps or blocks with a maximum overall size of 35x42mm.

The Roll-a-tector can find the watermarks of stamps that are still on postcards, envelopes or paper. It is efficient for difficult watermarks and general worldwide use. As the image of the watermark remains until the next stamp is inserted, this watermark detector can be used for studying a watermark or making comparisons. Any size can be checked.

Finding just one watermark variety may repay your investment in a watermark detector. The SG606 stamp is very common and usually worth very little; fortunately for our customer he checked the watermark. Are you sure you know the value of the stamps in your collection?