DJI Z Axis for Osmo Zenmuse Gimbal Model# OSP47 | eBay
Micro Pro 2 - 4th Axis – ScottyMakesStuff
4th Z Axis Detachable Gimbal Spring Dual Handle for DJI Ronin S SC RS2 RSC2 Zhiyun Crane 2S
Watch this before you buy the DJI Osmo Z-Axis - Hands on Review - YouTube
IDOLCAM 4th Axis, Z axis Stabilizer for Gopro, DJI, Insta360 and compact cameras under 400 grams. - IDOLCAM, All-in-One Vlogging Camera for Branding and Marketing!