Lot signal labels command your attention with their bright colors: red (with a stop, do-not-use message), yellow (with a cautionary, changes needed message) and green (with a go-ahead, ready-for-use message). Labels are stripped and perforated and will stick to almost any dry surface. You can write on them with a ballpoint pen or pencil. 1½ x 3 in. with a 1 in. core.