NET
22 Over the heads of the living beings was something like a platform, glittering awesomely like ice, stretched out over their heads.
Darby
22 And there was the likeness of an expanse over the heads of the living creature, as the look of the terrible crystal, stretched forth over their heads above.
KJV
22 And the likeness of the firmament upon the heads of the living creature [was] as the colour of the terrible crystal, stretched forth over their heads above.