A search has been launched to find the so-called lost Clickers of D-Day, as people prepare to mark the 75th anniversary of the Second World War landings.
The small brass items were a “vital piece of survival equipment” during the battle, producers ACME Whistles said.
The Clickers, sometimes nickel-plated, were used as a means of communication by paratroopers who were dropped into darkness behind enemy lines the night before D-Day.
The soldiers would click once to signify they were not alone when they landed or later detected the presence of someone else, and two clicks in reply meant the other person was a friend.
The equipment was to be used for 24 hours only and then banned, because it was assumed the items would be captured and replicated afterwards.
Birmingham-based ACME whistles said while replica and counterfeit Clickers exist, very few of the 7,000 originals made in the six-month run-up to D-Day have been found.
ACME Whistles managing director Simon Topman said: “To mark the 75th anniversary of the D-Day Landings we would love to find as many of the original Clickers as possible.
“Perhaps your great granddad was a D-Day veteran, maybe he has a box of war medals where it could lie unknown? Maybe an elderly neighbour is a widow of a D-Day veteran who doesn’t realise the significance of the unassuming Clicker?
“We ask that people start seeking them out, to see if they can unearth a lost piece of sound history.”
Catherine Davies, head of remembrance at The Royal British Legion said: “D-Day marked a turning point in the Second World War and changed the course of history.
“We honour the bravery and sacrifice of our D-Day veterans and we celebrate the hard won peace, democracy and diversity they fought for.
“As we commemorate 75 years since the Normandy landings it’s great to see organisations such as ACME find ways to thank this special generation, and we look forward to seeing what the search for the lost Clickers unveils.”
Anyone who thinks they may have an original ACME Clicker can contact Ben McFarlane at Ben.McFarlane@ACMEwhistles.co.uk, call 0121 554 2124 or message @ACME_whistles on Instagram.
The company plans to hold a commemorative day for veterans, friends and family who find and bring forward original clickers.