Halifax: basically an R action Darne. No orbtirator disk. Has 1 piece solid, brazed barrels. Usually a raised rib, special order swamped rib was available, no "plume" rib that is seen on most graded Darnes. Halifax is usually stamped in the key lever, the barrel flats will have the marking too with the addition of Darne license and the grade of Halifax. The grades are indicated by a number. Usually a 3 (common) thru #5. 5's having some additional options like engraving.

So in laymans terms....it's a very basic R action Darne.