More heavy-duty then their un-xtreme bretheren, MaxTrax's Xtreme recovery boards have replaceable aluminum teeth, and extra support for heavier vehicles.  

Product Features:

• MAXTRAX XTREME is also easily repairable in the field. If a tooth gets damaged, simply flip the board over and use a T-50 Torx bit to remove and replace the damaged tooth.
• MAXTRAX XTREME uses a proprietary and patent-pending thread & bliplock system to ensure secure physical engagement of a new tooth with its recess after replacement.
• MAXTRAX XTREME will nest with MAXTRAX MKII recovery tracks, (although there is a slightly larger space between the tracks due to the design of the underside of the MAXTRAX XTREME).
• Australian designed, engineered and manufactured
• 88 replaceable anodised alloy teeth; designed for XTREME users
• Safe and easy recovery from sand, mud, snow and slush
• Made from super-tough engineering-grade reinforced Nylon
• Compatible with MAXTRAX MKII and MAXTRAX Mini
• Proven, patent-pending, multi-award-winning design
• Weight: 9kg/20lbs per pair
• Six glove-friendly handles
• A variety of mounting and carrying options are available

Product Specifications:

• External Dimensions: Height 4 inch / Length 47 inch / Width 14 inch
• Product Weight: 20.3 lb
• Warranty: Lifetime
• Country of Origin: Australia