a needle safety device , which is usable on long , short , straight or curved needles , is actuated to enclose the injecting end of a needle when an engagement surface of the device is slid beyond the injecting end . a unitary or multiple piece clip is provided which is slideable from a first position wherein a hypodermic needle is usable for injection purposes to a second position wherein the injecting end of the hypodermic needle is covered rendering the needle unusable and protected .