Machins – Northern Ireland. 
The ubiquitious Machin stamp, named after Andrew Machin who created the original sculpture, appeared between 1971 and 2000 with the symbols of regions of the United Kingdom, Scotland, Wales, Man, and Northern Ireland. The Irish stamps have the drawing of the Red Hand of Ulster in the upper left of the stamp. (Figures 1-3). These stamps have been printed in most colors of the spectrum, and in values less than £1.00. More recent ones are seen bearing 1st class marking in lieu of a value.
Machins come in sheets, coils, and booklets. They have been printed with various perforation types and gauges by different processes, mainly photogravure and lithography. Some fluoresce in UV light, and different gum types are known. There have been minor changes to the artwork, in particular changes in the jewelry. The letter styles also may differ depending on the printer. In short, a lot of challenges for the collector.