[TVI-RFI-EMI] Clamp-On Ferrite Filter Any Good?

[doc]

Just spotted this "Clamp-On Ferrite Filter" in the 
Hosfelt online catalog, these effective for automobile 
noise problems?

Thanks! & 73, doc KD4E  ARRL-WCF-SEC
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http://www.hosfelt.com/Specials%20Folder/special1.htm
Clamp-On Ferrite Filter Mfg. - TDK
1-7/16" x 7/8" dia. Clamps open to a 3/8" dia. 
round cable. Provides excellent common mode 
EMI suppression. Great for network cables.
PART #  80-287 $ .99 (1-99)