An infusion set comprising: a housing comprising a housing septum , a blunt cannula , and a release device comprising a button ; and a base comprising a base septum and an infusion cannula into which the blunt cannula passes when the housing is attached to the base , the base further comprising a retention boss ; wherein when the housing is attached to the base , a part of the housing extends into and opens the base septum ; and wherein when the housing is attached to the base , an introducer needle can be extended through the housing septum , blunt cannula , base septum and infusion cannula ; characterized in that the release device further comprises: a movable keyhole latching device engaging and disengaging with the retention boss for attaching and detaching the housing to the base , the keyhole slot latching device comprising a movable keyhole slot having a larger diameter portion and a smaller diameter portion; and a spring , the spring being attached to the keyhole slot latching device and disposed externally to the movable keyhole slot wherein when the button is pressed, the release device actuates the spring to move the keyhole slot from a first position at which the smaller diameter portion is engaged with the retention boss , to a second position at which the smaller diameter portion is disengaged from the retention boss . a housing comprising a housing septum , a blunt cannula , and a release device comprising a button ; and a base comprising a base septum and an infusion cannula into which the blunt cannula passes when the housing is attached to the base , the base further comprising a retention boss ; wherein when the housing is attached to the base , a part of the housing extends into and opens the base septum ; and wherein when the housing is attached to the base , an introducer needle can be extended through the housing septum , blunt cannula , base septum and infusion cannula ; characterized in that the release device further comprises: a movable keyhole latching device engaging and disengaging with the retention boss for attaching and detaching the housing to the base , the keyhole slot latching device comprising a movable keyhole slot having a larger diameter portion and a smaller diameter portion; and a spring , the spring being attached to the keyhole slot latching device and disposed externally to the movable keyhole slot wherein when the button is pressed, the release device actuates the spring to move the keyhole slot from a first position at which the smaller diameter portion is engaged with the retention boss , to a second position at which the smaller diameter portion is disengaged from the retention boss . a movable keyhole latching device engaging and disengaging with the retention boss for attaching and detaching the housing to the base , the keyhole slot latching device comprising a movable keyhole slot having a larger diameter portion and a smaller diameter portion; and a spring , the spring being attached to the keyhole slot latching device and disposed externally to the movable keyhole slot wherein when the button is pressed, the release device actuates the spring to move the keyhole slot from a first position at which the smaller diameter portion is engaged with the retention boss , to a second position at which the smaller diameter portion is disengaged from the retention boss . <EOS>