Black Stained, U-Channel Framing Stock. Great for Stained Glass WorkCrafted from premium poplar wood, this Black Stained U channel framing stock delivers professional grade construction for stained glass artisans. Each set includes four pieces, with a smooth finish and ready for immediate application. The stained wood surface will compliment your stained glass well. Manufactured domestically with meticulous attention to quality, this framing solution provides the structural integrity and precision fit that serious