When driving passengers around they would often accidentally unbuckle my child's car seat when buckling in or unbuckling themselves. As it was a hassle to keep buckling it back in I've designed this which makes it impossible to unbuckle a seatbelt without the use of a car key or other small device.

This was tested on a 2023 Tesla Model Y rear seat buckle, though if scaled up or down it should be able to fit almost any car seat buckle.

OnShape Link: https://cad.onshape.com/documents/5d6722963138f155070f883d/w/80690e63594637d70f060f40/e/8dcaa547b6c05ed340da0f64?renderMode=0&uiState=65affdc8ccb15e33e4f28c77