The Passe-Partout trolley is designed to lock into the base of Camac pedal harps. The rear feet rest on the vertical part, while a metal peg slots into a notch in the base of the harp. The cart is then secured to the harp by means of an angled rod that fits into a sound hole at the back of the sound body.
In the case of use with a harp cover, it will be easier to use the cart without the base covers, as this allows continued use of the bass peg.
It is also possible to use the cart in full covers. In this case, it is not possible to lock the harp base onto the platform of the trolley, but the rod can still be hooked through the sound hole openings in the covers and onto the harp.