King MASH Composite Block for 12″ Guardrail Applications

King MASH Composite Blocks® are injection molded guardrail offset blocks composed of Recycled High Density Polyethylene (HDPE) and tested to AASHTO’s MASH, 2nd Edition (2016), Test Level 3 specifications. The King MASH Composite Block is offered as an alternative to 12″ (305 mm) depth wood blocks on W-Beam guardrail systems, utilizing standard W6x8.5# / 9# (W150x12.6 kg / 13.5 kg) steel posts.

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  • Eligible for reimbursement under the Federal-aid highway program, per FHWA letter HSST-1/B-353, dated 21 December 2020, as a MASH 2016 device.
  • Self-hanging fingers.
  • Self-aligning side rails.
  • Lightweight – only 7.0 lbs. (3.2 kg)
  • Weighs less than other 12″ MASH blocks.
  • Bottom tab supports rail during installation.



Assembly & Maintenance

  • Self-hanging fingers minimize the need for assistance by end-users during installation.
  • Self-aligning side rails are designed to hold block in place and resist rotation.
  • King Blocks are designed to retain their original size over time, which helps reduce the frequency of retightening guardrail post bolts.
  • Formulated with UV inhibitors, to reduce long-term degradation.
  • Weather-resistant materials minimize damage related to rain, snow, and extreme cold/heat.
  • Blocks are composed of durable materials resulting in less damage by ongoing roadway operations – such as snowplowing and mowing.
  • HDPE offers superior resistance to solvents, alcohols, acids and alkalis.


12″ King MASH Block

    • 4″W x 14″L x 11.5″D, 7.0 lbs. (3.2 kg)
    • (100 mm x 355 mm x 292 mm)


Truckload Information

  • 117 blocks per pallet/skid, weight of 875 lbs.
  • 5,616 blocks per truckload

Product Images

Product Documents

PI Sheet

King MASH Composite Block for 12″ Guardrail Applications