The frame grid. As the thin wire is wound at 50% of the breaking strain to eliminate any kinks, the supports need to be kept apart and her there are welded tapes top and bottom of the support.
A closer view of the frame grid.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 48 mm tall.
Reference: Data-sheet. Type 8532 was first introduced in 1964. See also1964 adverts.