Tool market in Guangdong?

This week, I’m going to China for the first time. I’ll be in Jiangmen, Zhongshan, Shenzhen and maybe Dongguan. At a previous job, we bought a bunch of tools at some kind of a tool or hardware market somewhere in Guangdong, but I don’t remember where it was. We bought a bunch of calipers, and some digital color analyzers. Real useful QC stuff.

Anyone have an idea of where I’m talking about or a place where I could stock up in Guangdong?