ultra-strong ABS, ferro-boron alnico and rubber strip. It is practical, solid, anti-fall and durable. Effective for single glazed windows 3-8mm thick. Due to the powerful magnetism, pay attention to your hand when closing or taking them apart. Unique Modern Design: Stay in the room to clean the interior and exterior window at the same time due to the magnetic design. Wide use: ideal for home windows, greenhouses, car windows, greenhouses, etc. Product Size (L x W x H): 6.3 x 5.3 x 2.8 in