I use what ever I’m using as a marker, usually a neon marker sold by uk putange, they are simple but effective, and long enough I can use them straight through the eye of putange an still more than enough left above ground to see, if ground is proper stony tho then the markers ain’t very good an I use a tent peg an give it a few taps, an try an get all the putanges set in the trap bed with eyes on top of each other so I only need to use one peg, and if it’s an undercover job then I use tent pegs an then a bit a marker paint a probes distance from the trap bed, if he ain’t using loads a putange