10 Pesos Pattern, Tuerca, Copper-Nickel

In the early 1970s, Mexico was actively redesigning its circulating coinage in anticipation of inflation-driven denomination changes, and the Mint produced a series of pattern strikes — known colloquially as "tuercas" (nuts or bolts, a nickname derived from the reeded or segmented edge treatment tested on some pieces) — to evaluate new specifications before committing to production tooling. The 1974–1976 date range suggests this piece survived at least two budget cycles without advancing to circulation, not uncommon for Mexican pattern work of this period.

The dual PL references (44 and 44B) indicate at least one recognized die or specification variant within the type.