Designed for 5/8 and 3/4 inch thick glass and acrylic, most glass tanks from 200 to 300 Gal. & most very large acrylic tanks up to 72 inch long and 36 inch high. The inside magnet projects 1/2 inch beyond the outer magnet. This extended reach allows cleaning beyond the visible edge of trims and canopies. Other advanced features such as ergonomic grip, replaceable pads for glass and acrylic, large 2.5 x 3.75 inch cleaning surface set this product apart from all others.