Just bought a PS4 Pro. The rubber grips on the underside are the buttons of the controller. I enjoy the little details like this - 9GAG
ps4 - What is this hole for in the controller? - Arqade
eXtremeRate White Dawn Remappable Remap Kit for PS4 Controller with Upgrade Board & Redesigned Back Shell & 4 Back Buttons - Compatible with JDM-040/050/055 - Controller NOT Included – eXtremeRate Retail
DualShock 4 Back Button Attachment review: small but perfectly formed | Eurogamer.net
How to Turn Off Any PS4 Model Without a Controller
PlayStation's DualShock 4 Gets Beefy With New Back Button Attachment | Geek Culture
eXtremeRate Chrome Gold Classical Symbols Custom Replacement Full Set Buttons for ps4 Slim Pro CUH-ZCT2 Controller - Compatible with ps4 DTFS LED Kit - Controller NOT Included – eXtremeRate Retail
DualShock 4 Back Button Attachment review - Polygon
What is the little hole on the back of the PS4 controller? - Quora
Just unpacked my pro and saw the bottom has the PS button symbols : r/PS4Pro
Amazon.com: DualShock 4 Back Button Attachment - PlayStation 4 : Video Games
Cronus Zen PS4™ DUALSHOCK®4 Back Button - Open Box – Lime Pro Gaming
Getting ready to move, and I noticed on the bottom of my PS4 pro, the rubber feet are the buttons from the controller. I love finding little details like that. : r/playstation
DualShock 4 Back Button Attachment review - Polygon