Many manufacturers just print the double arrows on sector and Trainload Freight loco models instead of providing etched stainless steel ones and in all scales. To suit 'O' gauge models. The etched range is slowly on the increase too.
7mm scale 'O' stainless steel standard BR Railfreight double arrows 1 pair.
SLATER's KITBUILT 12T Rectangular Tank Wagon 7mm Scale O Gauge SEE DES - PTA15
7mm scale O gauge compensated W irons 3 pairs
7mm Scale O Gauge 1/43 Pack Of 2 Resin Horses In Harness Model Railway
LASER CUT WHISTLE SIGNS FOR O GAUGE 7mm SCALE MODEL RAILWAY LX131-O
7mm Scale Station Building Kit Ideal For O Gauge, Trains, Trams, 1:43 Scale Cars