What is It? Game 15

This week's collaboration with What is it? Blog brings us this strange object - can you guess what it is? For more fun guessing game (and for dimensions clue on this object), check out What is It? blog.

[No prize this week - congrats to Kent who won last week's game]

Update 3/16/07: The answer is:

Aerial spacer cable insulator, allows the running of a three phase line in a minimum amount of space. The hook on the bottom left is hung on a steel messenger cable and the conductors are placed in the large inner grooves, with the small outer grooves being used for tie wires.

Congratulations to Chris who got it right!