This is only for classes that allow an optional non-SFI approved oil retention device. It is not meant to be used as an SFI approved type engine diaper that is ballistic capable.
The bottom of the oil retention device is padded with a doubled up oil absorbant pad.
From what I've heard, some tracks, if not all are going to demand that if your car is capable of 9.90 and quicker in the 1/4, you must have an oil retention device, regardless of whether it is optional according to the rulebook or not. It will be up to the individual track tech inspectors as to whether the device is worthy or not. The idea is to keep oil downs to a minimum so the show can go on. It's a good idea for drag racing. No one likes sitting in the pits, or spectator stands waiting for an hour or longer while the guys clean up an oil down.