The present invention relates to a supplementary device for a manually operable injection device, the supplementary device comprising: a body (300) having at least one engaging member (340) to releasably mount the body (300) to the injection device (1) in a specific position (P) on an outside surface (106) of the injection device (1), at least one indicator (350； 370； 380) located on the body (300) and having a shape or contour to overlap or to align with a mark (150； 160； 170； 180) on the outside surface (106) of the injection device (1) when the body (300) is in or near the specific position (P).
