SUMNER Ultra Clamp 781130 Pipe Clamp 1 to 2-1/2" Adjustable UC1-2.51 ea. Sumner UC1 2. 5 USA 781130 Ultra Clamp 1 to 2 1 2". This is a high quality Pipe Welding Clamp from Sumner Manufacturing. The ULTRA Clamp, model number 781130, is designed to securely hold pipes ranging from 1 to 2 1 2 inches in diameter. This black colored clamp is made of durable steel and weighs only 4 pounds, making it easy to handle. Whether you're a professional welder or just someone who needs to securely hold pipes in place, the Sumner