These multi-barred numerical brass obliterators were introduced in 1858-1859 and were in use until the introduction of the squared-circle dies in 1882. Fifteen different "styles" of the dies have been described (designated by the letters A - P). Of these styles A - G were only used at Kingston with the mark "AO1". The remaining styles (H, J, K, L, M, N, O and P) were used at offices throughout the island. In several cases an office used more than one style or the same number was allocated at different times to different offices. A set of five obliterator dies have only the single letters (A - E) instead of the more usual letter-numeral combination. The locations of use of some of these dies has not been determined.
* Sources for this material:Collett et al., (1928) pp. 198-214; Nicholson LCC (1949); Potter IA (1996) pp.16-20.