Devon & Cornwall Police are appealing to DIY shops and builders merchants for information about any recent sales they might have made of disposable decorator's outfits.
The overalls were worn by three men who carried out an armed robbery at a jewellery shop, House of Diamonds, in Paignton on April 22. The thieves got away with £7,000-worth of gold jewellery and injured the shop owner.
CCTV footage shows the men wearing hoody jackets over white disposable painter-and-decorator overalls. The police would like to speak to any hardware or DIY retailer who remembers selling three such items.
Det Sgt Sam Smoothy said: "These are the cheap, disposable suits that can be bought in a number of places. We are hoping to jog someone's memory who may have sold three of these suits recently."
Anyone with any information is asked to call police on 101 or anonymously through Crimestoppers on 0800 555111 quoting FP/14/1315.
Two of the suspects got away but the third was caught and has been charged in connection with the incident.