Wirsbo and Uponor are actually the same company. The company used to be called Wirsbo, but recently changed its name and is now called Uponor. If you have old PEX tubing, tools, fittings, or rings that say Wirsbo on them, Uponor parts are totally compatible. The exact same products are made now, and the standards of high quality, precision engineering, and warranties you can count on continue; the only change is a new logo.
Wirsbo products including PEX Tubing for PEX Plumbing and Radiant Heat products can be found at www.supplyhouse.com