Based on the specific markings, this lighter was manufactured between 1968 and 1981.
Model: Rollagas (Standard size).
Casing Pattern: Hobnail (also known as diamond-cut or pyramid).
Material: Silver-plated brass.
Date Range: (1968-1981) patent number “US. RE24163” stamped on the base. Dunhill used this specific format on Rollagas bases primarily during this period. Models from before 1968 typically used different patent language, while those after 1981 removed patent numbers in favor of a more prominent logo and "Swiss Made" text.
Features on the Base include: Large Circular Cap: This is the cover for the gas refueling valve. Small Screw/Port: This is the access point for changing the flint.
Side Feature: Small Scroll Style Wheel: This is the flame adjustment mechanism.
Please note, whilst this piece is in working order, it is sold without gas.