Designed for 1/4 and 3/8 inch thick glass and acrylic, most glass tanks from 30 to 125 Gal. & most acrylic tanks up to 36 inch long and 20 inch high. The inside magnet projects 1/2 inch beyond the outer magnet. T his 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. This Magnavore product features a one year warranty against defects in materials and workmanship. Huge performance at low cost!