A connection device for connecting a compressed gas cylinder to an inflatable device, wherein the connection device comprises: - a releaser configured to provide a fluid connection between the compressed gas cylinder and the inflatable device, the releaser comprising a releaser house formed with a central piston channel and an activation mechanism comprising a piston provided with a bunching dart for controlled puncture of the compressed gas cylinder, said activation mechanism being provided with means for axially displacement of the piston in the piston channel to-wards the compressed gas cylinder; - an outer sleeve comprising threads with a first handedness on an outside of the outer sleeve which fits complementary threads on an inside of an opening in the releaser house whereby the outer sleeve is configured for being fastened into the releaser by turning in a first direction relative to the releaser; and - an inner sleeve comprising threads with a second handedness on an outside of the inner sleeve which fits with complementary threads on an inside of the outer sleeve, and threads with the first handedness on an inside of the inner sleeve which are configured to fit with complementary threads on the compressed gas cylinder, whereby the inner sleeve is configured for being fastened into the outer sleeve by turning the inner sleeve in a second direction relative to the outer sleeve, and for the compressed gas cylinder to be fastened, in use, into said inner sleeve by rotation of the compressed gas cylinder in the first direction relative to the inner sleeve, characterised in that the second handedness is opposite the first handedness, in that the second direction is opposite to the first direction, and in that the connection device further comprises thread-locker on the threads between the compressed gas cylinder, in use, and the inner sleeve and between the outer sleeve and the opening of the releaser house, or in that the threads between the inner and outer sleeve have a larger pitch than between the outer sleeve and the opening of the releaser house, whereby the connection device is configured such that, when the compressed gas cylinder is fastened to the connection device, turning of the compressed gas cylinder in the second direction relative to the releaser will result in axial displacement of the compressed gas cylinder towards the bunching dart. - a releaser configured to provide a fluid connection between the compressed gas cylinder and the inflatable device, the releaser comprising a releaser house formed with a central piston channel and an activation mechanism comprising a piston provided with a bunching dart for controlled puncture of the compressed gas cylinder, said activation mechanism being provided with means for axially displacement of the piston in the piston channel to-wards the compressed gas cylinder; - an outer sleeve comprising threads with a first handedness on an outside of the outer sleeve which fits complementary threads on an inside of an opening in the releaser house whereby the outer sleeve is configured for being fastened into the releaser by turning in a first direction relative to the releaser; and - an inner sleeve comprising threads with a second handedness on an outside of the inner sleeve which fits with complementary threads on an inside of the outer sleeve, and threads with the first handedness on an inside of the inner sleeve which are configured to fit with complementary threads on the compressed gas cylinder, whereby the inner sleeve is configured for being fastened into the outer sleeve by turning the inner sleeve in a second direction relative to the outer sleeve, and for the compressed gas cylinder to be fastened, in use, into said inner sleeve by rotation of the compressed gas cylinder in the first direction relative to the inner sleeve,