Good magnet, fast delivery - but it didn't solve my window blind problem.
Review by confirmed purchaser
I have double-glazed windows with internal venetian blinds (the blinds are made by ScreenLine). The blinds operate with an external magnet (turned by pulling a cord) which couples through the glass to an internal magnet, which, as it is turned, raises and lowers the blind. Just outside its 5 year guarantee, one of the blinds got stuck in the up position, and wouldn't lower. You could hear the magnet clicking as it tried to turn the internal magnet, but it didn't move. So I contacted the window suppliers (Sunfold Systems) who said that sometimes, if their fitters encountered this problem, they used an "extra-strong magnet" to get it moving. So I bought what I thought was a suitable magnet from First4magnets. This certainly coupled strongly to the internal magnet - but unfortunately failed to turn the internal mechanism. So I now face a £600 bill for a completely new window with new internal blind mechanism. That's the problem with sealed units - you can't get inside to fix them.