Spare batteries for 878's often ship without a clip, and the clip is hard to find/expensive. So after 15 mins on Fusion 360 and a few grams of ABS later…
Be warned: you'll need a couple of M2,5 screws.
AT-D878UVII_Belt_Clipv2.stl | 310.6KB | |
AT-D878UVII_Belt_Clip_v3.f3d | 208.1KB |