Welded wire is that 2x4" or the 1x3" strong wire. It's used for dog pens and stuff. I LOVE IT. If you use this with hardware cloth, or chicken wire at the bottom to hold in young ones, it is usually predator proof at the sides. I learned a stressful way that chicken wire alone will NOT hold back our pitt bull. Not anything against her breed, but she just busted through my wire. I'm glad she couldn't get through the pop door. Hardware cloth is the little squares, strong, but costly. It is the only think I found that holds serama chicks. My 3 week old Seramas can get through chick wire.