adjuster cap 30 u2032 both rotates due to its engagement with the cover 150 via the shafts 157 and moves axially with respect to the cover 150 due to its threaded engagement with the retainer 25 u2032 the pressure regulator 10 u2032 also includes a catch or detent mechanism 158 arrangement for locating the cover 150 in a desired angular position with respect to the retainer 25 u2032 each of a plurality of recesses 160 define a plurality of angular positions relative to the base 15 u2032 the cover 150 includes a depending flexible tab 162 adjacent the cover periphery the tab 162 includes an inwardly extending projection 164 fig4 the illustrated projection 164 is hemispherical in shape and each of the recesses 160 are substantially semi cylindrical in shape however other suitable mating shapes may also be used as can be determined by one of skill in the art with reference to fig2 the catch mechanism 158 is constructed such that the projection 164 is biased into engagement with a recess 160 by the inherent biasing force of the flexible tab 162 as a result the cover 150 and thus the adjuster cap 30 u2032 are held in one of the annular positions defined by the plurality of recesses 160 when the cover 150 is rotated relative to the base 15 u2032 with a sufficient force the projection 164 is disengaged from its current recess 160 and moves into engagement with the next adjacent recess 160 in the direction of rotation of the cap 150 preferably the inherent biasing force.