Indonesian Insulator Protector

I would like to share with you something that I have learned recently. The following information came from the Buerstetta family here in Houston. A friend of theirs, Colin Eldridge of Menlo Park, California, works for Bechtel, Inc., a large U.S. engineering firm. Since he is a railroad engineer and a specialist in his field, he makes trips to exotic places like Australia, Tasmania, Africa, South America, etc. A typical assignment for him would be to travel up the Amazon River in South America, and then go back 300 miles into the interior to see if it would be possible to build a railroad to carry out products such as gold or iron ore from mines found deep in the jungle. Colin keeps his eyes peeled for insulators each time he makes such a trip, and brings them back to Dale and Regina Buerstetta, who have many collections going -- insulators being one! Their most recent "surprise" was a pair of insulator protectors that Colin brought back from Sumatra. It seems that while he was traveling along the railroad he noticed these strange coverings on all the insulators, and voiced his curiosity to the natives he was working with. To his amazement, two of these deep aqua colored covers were delivered to his hotel room next morning. They were a gift! 

Unfortunately, there are no markings on them, and the insulators were not included, so we have no idea what the insulators looked like or exactly how the covers were attached to them. This cover actually looks like an inverted bowl, and if you can think of it that way, it is 4-1/2" inches deep and is 7 inches wide at the rim. At the exact center of the bottom (or top, when it is inverted) of the bowl is a 3/4 inch round hole. There are two metal washers meant to be used here somehow, perhaps one inside and one outside the cover. On one side of the base is a crudely hand cut window 4 inches by 7/8 inches, probably for the wires to go through. Following is the information about it as told by Colin to the Buerstetta's son, Dan.

"If you were to ride the Indonesian National Railway (3-1/2 foot gauge) through the Island of Sumatra, you would soon notice green bell shaped housings covering every insulator which parallels the narrow gauge tracks. These tough fiberglass units were installed to protect the insulators from slingshot toting "water buffalo boys". Water buffaloes are widely used agricultural aids which require watering often. Young boys lead the beasts from the fields to the watering holes. Along the pathway, powerline insulators are objects of temptation for target practice. Because the insulator breakage problem was so pervasive, the power company devised these protective covers and installed them over all insulators in this section of Southeast Asia." 
Dan Buerstetta 
Houston, Texas