The first two shown were produced by Armstrong as salesman samples. The example on the far right is a reproduction copy that appears to be made by using the original mold. It can be identified by not having a strong embossing of the "A" in a circle found on the front and rear skirt of the insulator.

far left example embossed: [010] (F-Skirt) "A" in a circle (R-Skirt) "A" in a circle. (Base of pedestal) Armstrong's WHITALL TATUM COMMUNICATION INSULATORS {CD 155 style on a glass pedestal}

2 1/4" x 2 7/8"

middle example embossed: [010] (F-Skirt) "A" in a circle (R-Skirt) "A" in a circle. (Base of pedestal) Armstrong's WHITALL TATUM DISTRIBUTION INSULATORS {CD 216 style on a glass pedestal}

2 1/4" x 2 7/8"

Far right example embossed: {may have a very faint "A" in a circle on front and rear of skirt} (Base of pedestal) Armstrong's WHITALL TATUM DISTRIBUTION INSULATORS {CD 216 style on a glass pedestal}

2 1/4" x 2 7/8"

The SI 216 - 2.250 style also found in Amber.

Also listed as SI 216 - 1.50 these are found without the pedestal in Clear and Amber