These sleds make use of the bottom mounting channel on the router and requires 2 screws (Philips Pan Head screw #6-32×3/16 according to Teltonika) for a secure mount. (This will mark your router as the screws tap into the channel)
The design might work for other RUT routers but the 240 is already over-sized for the 1W sled so ymmv.
The author remixed this model.