A stealthy way to hide an Air Tag under your bike seat ( modeled to fit the 27.5" Mountain bike Rockrider ST 120 Disc Seat: https://www.decathlon.co.uk/p/27-5-inch-mountain-bike-rockrider-st-120-disc/_/R-p-305496).
The two pieces clamp together using M3 hardware. Use the bolt length that works best for you (I used 8mm).
The author remixed this model.