The DX-9000-XLT model has an adjustable width setting that allows the non power side runway to be extended out another 4". The drip trays that come with the DX-9000-XLT will not fit on the wider setting. The drip tray extensions provide an easy solution to still allow use to use your drip trays. You attach the extension pieces to your drip tray using pop rivets. One set includes 8 extensions to modify 4 drip trays.