Beginning with the 1996 model year, a regulated feature requiring that the lap portion of a vehicle belt "can be used to tightly secure a child restraint system" without "any device that must be attached by the vehicle user to the seat belt webbing, retractor, or any other part of the vehicle," and "shall not require any inverting, twisting or otherwise deforming of the belt webbing" (FMVSS 208, S7.1.1.5).