Copper rig question

[GAMBLER]

How do you guys tell your what rod is your 400', 500', and 600' coppers? I have all of my coppers on the same exact kind of rods. I can tell the 100', 200' and 300' apart because they are all different sized reels. I'm going to pick up 2 more and want to see what ideas guys have for telling which one is which.

[SkeinMachine]

Take a black sharpy and right on the side of the reel 400,500 or 600.

Know at a glance

Plus it's easy to wipe/clean off if you change the length.

H.I.H.