Here are four less common pieces made by NZI (New Zealand Insulators) as follows: (Actual postage additional)

U-1145 Inkstamped NZI in a circle -- good condition -- $8

U-1569 N.Z.I. incuse on top -- good condition -- $15

U-tbd N.Z.I. incuse on top -- good condition -- $15 (unusual as no extended skirt!)

U-1408 7Z on top -- good condition -- $12 (SOLD)