A needle containing medical device having a retractable needle [90], the device comprising an outer body [93], an inner member [97] which can slide within the outer body, a releasable needle holder [91] in a front portion of the outer body, a needle attached to the needle holder, the inner member being provided with a series of spaced needle holder engaging means [108] , and the needle holder being provided with a series of spaced inner member engaging means [108] thereby enabling the inner member to be attached to the needle holder at at least one of the series of engaging means.
