The Rotur Sierra Pen Brass Tubes feature precision-cut brass tubes designed to fit the Rotur Sierra Twist Pen Kits and the Rotur Elegant Beauty Pen Kits. These tubes provide a sturdy and durable foundation for your writing instrument. Crafted from high-quality brass, these tubes are perfect for creating elegant and durable pens that are sure to impress. The pack includes five brass tubes. Spare tubes 5 pack: PSBT5