X-Chock Wheel Stabilizer
Provides added stabilization and prevents tire shifts by applying opposing force to tandem tire applications
Metal
X-style
Camco Plastic Wheel Chocks
Your basic, cheap plastic wheel chocks
Plastic
Wedge
MaxxHaul Rubber Wheel Chocks
Durable rubber wheel chocks - they're solid rubber and heavy-duty. Main drawback is they smell pretty bad at first ;)
Rubber
Wedge
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Why you need it
You don’t want your RV rolling off, do you? ;) Chocks will prevent that. They can also get you more stability in your {home}, preventing back and forth rocking
Decisions to make
Plastic vs rubber
Plastic chocks are much cheaper and lighter-weight, but not nearly as durable as rubber. If you have a very heavy fifth wheel, motorhome, etc... It's probably a good idea to use rubber
Wedge vs X-style
Most people who use the X-style use them in combination with the wedge style. The advantage of X-style is added stability (less back and forth rocking), whereas wedge chocks are generally much cheaper
Helpful Videos
Chock-type stability comparison