A trim of a check valve includes a stem, a fixed member including two opposite through holes, a rotational member secured to the stem and including two opposite recesses, a hollow coupling member including an inlet at one end, a sleeve releasably secured to the coupling member wherein the sleeve includes an outlet at an other end and the fixed member and the rotational member are disposed at one end of the sleeve, a closing member moveably disposed at an other end of the sleeve, a connector releasably secured to an other end of the stem, and a biasing member biased between the closing member and the connector. In response to fluid pressure differential greater than a predetermined value the rotational member is clockwise turned to align the through holes with the recesses to allow the fluid to flow out of the outlet.