This is what I am told is a U-964 two-piece glazeweld porcelain cabletop insulator. The mottled glaze nicely camouflages the Victor multipart R= ∞; logo, but it is visible as shown. The insulator has a large diameter somewhat crudely-made pinhole, and it is in remarkable shape for its age, with only a tiny flake off the corner of a wire ridge. Inquiries welcome.