A mantle (peribolaion). Old word for covering from pariballō, to fling around, as a veil in 1Co 11:15, nowhere else in N.T.
Shalt thou roll up (helixeis). Future active of helissō, late form for heilissō, in N.T. only here and Rev 6:14, to fold together.
As a garment (hōs himation). lxx repeats from Heb 1:11.
They shall be changed (allagēsontai). Second future passive of allassō, old verb, to change.
Shall not fail (ouk ekleipsousin). Future active of ekleipō, to leave out, to fail, used of the sun in Luk 23:45. “Nature is at his mercy, not he at nature’s” (Moffatt).