The invention relates to a compression connection means for an auto-injector (A), wherein the compression connection means adapted to attach a front-end device of the auto-injector (A) to a back-end device of the auto-injector (A) comprises of an annular mounting sleeve that is axially displaceable parallel to a longitudinal axis (X) between a locked position (L) and an unlocked position, a mounting sleeve spring biasing the mounting sleeve towards a locked position (L), at least one latch arm connected to one of either the front-end device or the back-end device, wherein the latch arm is deflectable in a radial direction, wherein the mounting sleeve in the locked position (L) is arranged to prevent the radial deflection of the latch arm and wherein the mounting sleeve in the unlocked position allows for a radial deflection of the latch arm, so as to allow the latch arm to be deflected on assembly or disassembly of the front-end device to the back-end device and to latch to or unlatch from the other of the front-end device or the back-end device.
