YellowJackets set up in seconds and warn people away from hazards. Two YellowJackets fold flat, stack neatly for storage to only 9 inches thick, and are made from HDPE plastic and exceed federal crash test standards. Rubber rings are available as ballast in high traffic or wind areas. Special holes accommodate, signs, lanterns and accessories. YellowJackets are equipped with highly reflective 3M sheeting.