Although an aluminium rear warning sign is only legally required in Italy it made sense to go that way as alternative versions were made from corrugated plastic and reviews showed they didn't last long unless you purchased the costly bike cover (with the warning sign plastic pocket) to go with it. This one was very competitively priced. Haven't used it yet but assume it does 'what it says on the tin'. Quick response to order and only negative was damage (bent etc) to one of the corners in spite of fairly good packaging. However as that was down to the courier service and I'm sure it will suffer far worse in use - hey ho.