ELEGRP Digital Dimmer Light Switch for 300W Dimmable LED/CFL Lights and 600W Incandescent/Halogen, Single Pole/3-Way LED Slide Dimmer Light Switch, Wall Plate Included, UL Listed, 1 Pack, Matte Black - Amazon.com
Installing dimmer in four way switch circuit - DoItYourself.com Community Forums
Help needed with 4-way Caseta dimmer + accessory switch wiring configuration : r/Lutron
How To Wire A 4-Way Switch
Best 4 Way Smart Light Switches — OneHourSmartHome.com
Dimmer for 4 way switch system - DoItYourself.com Community Forums
electrical - Does it matter which 3-way switch I put a dimmer at on a 4-way circuit? - Home Improvement Stack Exchange
Can you wire a lutron maestro dimmer on a 4-way switching system? - Quora