For a long time we have been asked the MAG-Float guys to make this for us and they have done a fantastic job. The stainless blade seems to remove a full 65mm width strip of algae from the glass with a single pass, whereas other blades seem to miss patches and start to deteriorate after a few uses.
The relatively high cost of the XL MagScraper version reflects the high levels of rare earth magnet material used however it is comparable with other magnets cabable of use on such thick glass. It can be used for glass thicknesses between 10 and 19mm but will also work on 24ml glass too if care is taken.This is a must for use aquatic shops too as it halves the cleaning time and gets into places that a normal magnet will not reach.
MagScraper extra large, for 19mm glass - dimensions for inner or outer magnet: 115mm L x 64mm W x 25mm D ( not including blade )