I like to use long antennae on my higher output multirotor builds, but this makes transportation awkward unless you remove the antenna.  I typically use stubbys just tp make sure that I dont burn my VTX plugging in a battery without something to dissipate that RF energy.  but Im absent minded, and I may forget to remove the stubby or a dummy load terminator.  this allows me to put a visible flag that should hopefully even clue me in before I fly.  

any terminator or choice of flag should work.  the terminator dimensions from bast to tip 16mm.  6mm diameter with a 8mm (7.8mm) hex.  I made these a little snug to hold better.  

terminators  https://a.co/d/8zjd6ld

flags https://a.co/d/iHwoJ3t