A support post for releasable fixation between a first and a second floor, comprising: a first and a second elongate member telescopically connected to one another, first floor and second floor engaging members positioned at the ends of the first and second elongate members, a displacement unit for displacing the first floor engaging member, a spring biasing the first floor engaging member in a direction away from the first elongate member, the first floor engaging member being moveable in towards the upper end of the first elongate member against the force of the spring, a first inspection window in the first elongate member, a second inspection window adjacent to the first inspection window, an indicator having a first marking arranged at the second inspection window in a relaxed state of the spring, and having a second marking arranged at the second inspection window in a loaded state of the spring.