SUMMARY: This final rule@ the first of two under the designation RIN 2127?CAJ44@ amends a provision in Federal Motor Vehicle Safety Standard No. 213@ ????Child restraint systems@'' that permits NHTSA to allow manufacturers of child restraint systems (CRSs) manufactured before August 1@ 2010@ to choose to have NHTSA test the CRSs with either the Hybrid II 6-year old child (H2?C6C) dummy or the Hybrid III 6-year-old child (HIII?C6C) dummy. This final rule amends the provision to permit manufacturers of currentlymanufactured CRSs the choice of NHTSA testing their child restraints with either the H2?C6C dummy or the HIII?C6C dummy until further notice. While the HIII?C6C is an advanced test dummy with state-of-the-art capabilities@ NHTSA believes the agency should complete ongoing research programs to improve the usability of the HIII?C6C dummy in FMVSS No. 213 before testing child restraints solely with this crash test dummy.