6" x 18" Master Channel Mount Power Trowel Finish Blade ProForm® Troweler finish blade, channel mount. Each 6" x 18" Master Channel Mount Finish Blade is designed for longer life and greater performance. 6" x 18" Master Channel Mount Power Trowel Finish Blade are made of heavy-duty steel to exacting specifications. 4 pack of 6" x 18" Master Channel Mount Power Trowel Finish Blade.