A precise, well-marked site saves you time and money. With Blackburn factory-direct pricing and the industry's fastest turn-around time, you'll save even more. And heavy-duty Blackburn flags stand up to abuse. Made from a durable 4 mil, mildew resistant plastic, Blackburn marking flags are permanently attached to a sturdy 15-1/2 gauge steel wire or 1/8" diameter non-conductive, plastic post. These flags are available in a variety of sizes and 13 brilliant colors including those recommended by the APWA.