I'm looking for seat belt extenders for the rear seats of my wife's Model 3. My twins are in booster seats and it is very difficult to buckle the existing belts with booster seats in place. I tried these extenders from Amazon but they seem to be the wrong size: https://smile.amazon.com/gp/product/B0797NDG48/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1 The width of the "tongue" of the extender and the size of the hole in the tongue (sorry if this is starting to sound a little risque) are the same as the existing Model 3 tongue. The extender will lock into the existing buckle in the car. However, the tongue of the car's belt will not lock into the extender's buckle. The Model 3 tongue is much shorter than the tongue on the extender. Anyone found an extender that works in the rear seats? I tried a forum search but didn't see any relevant threads.