Robbers restrained a sales assistant to snatch 14 mobile phones from a shop in Ruislip in broad daylight.
Sales assistants at the High Street Vodafone store were shocked and frightened when four men barged into the shop wearing distinctive yellow Marigold gloves.
Hillingdon police are appealing for witnesses to come forward with information on the robbery, which took place on April 2, at around 10.40am.
The men entered the phone shop and ordered two female sales assistants to go to a back room.
As one of the women tried to back away, she was restrained and dragged to the rear of the store, police said.
The suspects demanded the keys to a locked cage containing brand new mobile phones. They got the keys and stole 14 handsets, all worth around £500 each.
The men, who are believed to be in their teens or 20s, then fled down Midcroft. Police say it is possible they entered a vehicle.
The four men were wearing dark clothes, hats and hoods and distinctive yellow Marigold gloves.
DC Anji Dawson said: "The female staff involved are still understandably shocked and frightened about what they encountered that day.
“Clearly the men were prepared to use force if the women did not comply with them.
“There is a distinctive feature to all the suspects - the yellow washing up gloves they were wearing.
"The High Street was busy that time of the morning and there would have been many witnesses. I urge anyone who saw the suspects or what happened to call us."
If you have any information please call Uxbridge CID on 020 8246 1732 quoting reference 0906811/15; or if you wish to remain anonymous call Crimestoppers on 0800 555 111.