Amazon.com: eXtremeRate Black Soft Touch Game Improvement Replacement Parts Back Housing Cover, Custom Bottom Shell Compatible with ps4 Controller JDM-040, JDM-050 and JDM-055 : Video Games
PS4's Back Button Attachment Is Impressive, Comfortable, and May Tease the PS5 - IGN
Amazon.com: Sony Dualshock 4 Back Button Controller Attachment (PS4) : Video Games
Amazon.com: eXtremeRate Soft Touch Black Dawn Programable Remap Kit for PS4 Controller with Upgrade Board & Redesigned Back Shell & 4 Back Buttons - Compatible with JDM-040/050/055 - Controller NOT Included : Electronics