We manufacture 3 different types of filters: Gold Frame, Silver Frame and Flexible Frame. The Gold Frame filter is made from an extruded gold-anodized aluminum, comes in 1" size and is our sturdiest frame filter. The Silver Frame filter is made from roll-formed aluminum and comes in 1/2", 1" and 2" sizes. The Flexible Frame filter has no metal frame. It is manufactured with a material frame that is made to bend or twist for applications that require bending the filter to install/uninstall.