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 (1) of the auto-injector (A) to a back-end device (3) of the auto-injector (A) comprises - an annular mounting sleeve (1.11) that is axially displaceable parallel to a longitudinal axis (X) between a locked position (L) and an unlocked position, - a mounting sleeve spring (1.7.1) biasing the mounting sleeve (1.11) towards a locked position (L), - at least one latch arm (1.1.2) connected to one of either the front-end device (1) or the back-end device (3), wherein the latch arm (1.1.2) is deflectable in a radial direction, wherein the mounting sleeve (1.11) in the locked position (L) is arranged to prevent the radial deflection of the latch arm (1.1.2) and wherein the mounting sleeve (1.11) in the unlocked position allows for a radial deflection of the latch arm (1.1.2), so as to allow the latch arm (1.1.2) to be deflected on assembly or disassembly of the front-end device (1) to the back-end device (3) and to latch to or unlatch from the other of the front-end device (1) or the back-end device (3).
