I made my own out of some 1/8" sheet metal. The factory ones are not made out of very thick metal!
Dimensional drawing of my home made skid plate:
Factory Skid Plate Part Numbers:Belly Pan Front Skid Plate, PN: 52129093AF [Without Front Suspension Skid Plate]
SUPPORT ASSY. Front Belly Pan PN: 52129290AC
TRANSMISSION SKID PLATE, PN: 52125468AC
SKID PLATE. Transfer Case, PN: 52125249AB
Fuel tank skid plate PN: 52100332AH

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Supporting Vendor and Moderator of LOST05 Jeep Liberty CRD Limited 
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount98 Dodge Cummins 24 Valve