A Core deposit is a form of deposit you pay until returning your old part. If you don't have the core at the time of purchase, you must pay the core charge. That charge is refunded to you when you return the core.
LuK: Dont gamble stay with the original LuK DMF! The LuK DMF prevents damages solid flywheels may cause. The LUK Dual Mass Flywheel (DMF) is individually fine-tuned for every type of car. The risks of using solid flywheels are numerous from increased wear of engine mounts through gearbox failure to damaged crankshafts.