MJT 2291 Brass Compensation Unit. (4mm Scale EM Gauge). Includes one brass fret. No paper instructions included. They are in the photograph above.
HORNBY SOUTHERN RAILWAY UTILITY VAN OLIVE GREEN '2291'- UNBOXED
Great Western Railway. GWR - Luggage Label (2291) Ashton Devon
UK RAILWAY PHOTOGRAPH OF CLASS 47 47805. RM47 (2291)
Rapido Trains 978019 OO Gauge GCR ‘Evolution’ Non-Corridor Third No.2291
MJT Scale Components 2804 Lner Standard Coach Dynamos