Ps are using the Accufix Atrial 'J' Lead Pacemaker Model 330-801 and Model 329-701 (J Lead). Ds are a Delaware corporation and a separate Holding engaged in the business of designing, manufacturing, and marketing medical devices. D manufactured the J Lead pacemakers Models 330-801 and 329-701 from 1988 until 1994. The holding company's sole business is to hold certain industrial property rights, real estate, and the equity interest D. Defendants, Pacific Dunlop Limited (PDL), and Nucleus Limited (Nucleus) are Australian corporations. Nucleus is a holding company involved in the medical products industry. Nucleus owns a group of companies that design, manufacture, and sell pacemakers and defibrillators around the world under the trade name 'Telectronics Pacing Systems' or 'Telectronics.' Ds are the two of those companies that operate in the United States. In 1988, PDL purchased Nucleus and thus became a beneficial owner of Ds. The J Lead pacemakers have a retention wire that is encased in polyurethane insulation and bends back and forth within the system. The bending has caused the retention wire to break and poke through the insulation. The retention wire is not electrically active in the pacing circuit. A fracture can cause serious injury to the heart or blood vessels if it pokes through the polyurethane. Between December 1988 and February 1993, there have been at least seven fractures of 'J' Lead retention wires of the 25000 implanted in the U.S. By August 1996, there were at least thirty-two injuries due to fractures, including six deaths. Eight others have died while having their lead extracted. Ps sued Ds in 1995 in product liability, alleging injury due to a defective J lead. The Court initially certified a worldwide class for the common issues of medical monitoring, negligence, strict liability, fraud, misrepresentation, and breach of warranty. The Court granted Ds' motion to reconsider and decertified all the classes. Ps have filed a Renewed Motion for Class Certification. Ps want to certify only four causes of action as a class action: medical monitoring, negligence, strict liability, and punitive damages. Ps seek to certify this action against only Ds; they have not sought certification against the Australian Defendants.