Product review (4 stars): Satisfied
Worked for my whirlpool WFW8400TW02 - Front Load Duet Series.

Unit requires four.

Build quality of the shock absorbers were surprisingly cheap considering the cost, but they perform admirably better than the absorbers that the unit was built with.  The OE parts were all plastic construction, so these must have some benefits to them.

Overall I'm not disappointed with the purchase, just wish it would have fixed my problem.  Despite a level washer, spin cycles are still unbalanced, but at least now the unit doesn't vibrate the entire house.