Well $12 for 12 dB, i.e. $1/dB 
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I also have its little brother, worked good, for about a year, but recently I have replaced it first by DIY V-Stub on mag-mount and later by DIY QuickSpider with V-Stub, both performed much better.
Will order the $12 one now, just to satisfy urge to find out how good/bad it is.