Does anyone have any experience of these Matesy viewers: http://matesy.de/index.php?option=com_content&view=article&id=56&Itemid=75&lang=en I'm wondering how its sensitivity compares with the Sigma & Arnold magnetic viewers. Thanks in advance Nigel Nigel Champion Manager & Audio Conservator Archive Of Mâori & Pacific Music The University of Auckland Private Bag 92109 Auckland 1142