Royal Engineers TRF Badge cufflinks.
A Tactical Recognition Flash (TRF) is a coloured patch worn on the arm of combat clothing by members of the Royal Navy, British Army and Royal Air Force to distinguish their Regiment or Corps in the absence of a cap badge. It is similar to but distinct from the DZ Flashes worn by members of Airborne Forces. The colours of the TRF are sometimes derived from the unit's stable belt.