I have no idea who makes these things, and after multiple Internet searches on "Wonder Wand" turned up sex toy after sex toy I had to call it quits when my hand cramped up... from typing, you pervs!
These come in sets of ten, including eight orange flags for general use and two red flags for danger spots. I'll make a pitch for using two wands in an X for indicating danger, which is a better visual mark.
Just over an ounce each. 1.15 to be exact. Yes, I weigh everything.