Dunno but they can sure as hell punch through a hoodie. My wife was straightening up the apartment back in Texas after a fishing trip and one of those caught a ride on my tackle bag that was sitting by the front door. It jumped up on her arm, bit her through her hoodie and then tried to work its way under her sleeve. She threw it off of her and when it landed it started charging right back at us. I grabbed a huge bottle of Ortho Home Defense and started spraying it in the face and it had no effect other than the force of the spray keeping it back. It was covered in babies and they all started falling off dead but the big one didn't give two shits. I yelled at my wife to grab my gun off the night stand (I'm not even kidding) and while she ran to do that I ran out of spray poison and it kept charging at me. I grabbed the first thing I could, my flip flop, and proceeded to beat it like a red headed stepchild. I killed it... but I thought it may have just been unconscious because there was no squish or visible damage... it was just motionless with its legs curled up.
I took it outside and threw it on a fire ant mound. They wanted nothing to do with it. My wife's arm had some serious welts from the bites. She said it felt like being stung by a ton of hornets all at once. I have a pic of the dead spider I'll post tomorrow. It was the same size as the one Chad posted.