The Extended Density (ED) 3.5-inch Microfloppy was an advance on the High Density version (HD), with improved oxide coatings that offered 2.88 MB of storage.
It was introduced on the NeXTcube, NeXTstation and IBM PS/2 model 57 in 1991, but by the time it was available, it was already too small in capacity to be a useful advance over the HD format and never became widely used, while the HD format continued to be used until the late 2000s.
Like the HD microfloppy, the ED disk had an identification notch on the right-hand side, with this being slightly higher than the HD one, but the disk was otherwise the same size.
Dimensions: 94 mm × 90 mm × 3.3 mm
Capacity: 2.88 MB