Air-Craft Models ACA72044, Westland Whirlwind HCC.8 / 12, step & pitot, a photo-etch accessory set in 1/72nd scale.
 
VIP versions of the Whirlwind helicopter, and particularly the HCC Mk.8 & HCC Mk.12 aircraft operated by the Queen's Flight has a prominent step below the main cabin door to ease embarkation. 
 
This accessoy set provides the steps themselves in etched brass, together with a pitot head (absent from the Italeri kit). Plans are supplied to enable the modeller to fasion the step support and handrail from the brass rod supplied.
 
This item was originally available in the Whirlybird Kits range.