A: Juan, are you having some trouble over there?
B: Yeah, my wrench isn't fitting over this bolt.
A: Well, you're using the wrong wrench.
B: Really? It has the correct measurement on the side.
A: That's a measurement in centimeters - not inches. You could do some damage trying to use that one.
B: I did't realize I had the wrong one!
A: Come on. I'll show you where we keep the conversion chart

Which tools are required?
What is the measurement system speaker A mentioned?