An apparatus comprising an activation mechanism (20) operative to deploy a needle (116) to protrude out of a housing and to activate delivery of a substance through said needle (116) and a safety latch (122) movably mounted on said housing and formed with a needle opening (129) to allow said needle (116) to pass therethrough, wherein said safety latch (122) has a first position wherein said needle (116) is aligned to pass through said needle opening (129) and a second position wherein said safety latch (122) is moved with respect to said housing and said needle (116) is blocked by a portion of said safety latch (122) distanced from said needle opening (129). (Fig. 12)
