If you do not want to transport the rack, then it may be sufficient to either just place the device on the rack adapter or just fix it with double-sided adhesive pads.
Please note when using these adhesive pads, do not remove the original feet under the ADI-2 Pro, it is best to stick the double sided adhesive pads under the feet. Only this way the ADI-2 Pro has enough distance from the supporting surface to ensure that the heat generated at the bottom of the device can be dissipated by an air flow.
Normally such a device would be fix attached to the rack adapter by screws, so that the heat could be dissipated by the rack adapter, but this is not possible here, because the ADI-2 Pro has not such holes and the question is whether the heat dissipation by this rack adapter would be sufficient for the ADI-2 Pro FS R BE.
If you use this rack adapter, then leave a little space to the other devices, so that the rack adapter does not heat up too much and the heat also does not accumulate upwards.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13