Astria 60-inch Variable Speed, Heat Activated 2-piece Blower Kit FBK-LIN-BAstria 60 inch Variable Speed, Heat Activated 2 piece Blower Kit FBK LIN B Product Details This blower kit may be used with gas fireplaces listed herein. The FBK LIN B blower kit is used when a unit mounted variable speed blower control is desired. The blowers are installed beneath the rear of the firebox. When the fireplace reaches operating temperature, the thermal switch will turn on the blowers. Room air is drawn in through the bottom area of the