A valve with an on-off mechanism for a bag used for conditioning, reconstituting, and/or diluting of injectable products, with the valve integrated to the single access point of a bag； the valve includes an open-close mechanism that enables a syringe or an infusion equipment, both including a luer-lock terminal, to be directly coupled to said valve； the valve comprises five basic components: the tapered base, the mobile tapered part, a smaller diameter sealing O-ring, a larger diameter sealing O-ring, and the cover that protects the terminal with a luer-lock type thread； the valve removes the requirement of using metallic needles or plastic spikes during practical use of the bag.
