7-hole Venturi Bolt

[Babalui]

Being quite new, I may be surfing too much, so I run into this item on ebay:

Pro Line Spyder Java Compact 7-hole Venturi Bolt



I like this part of description:

Fits all mechanical Spyders (and some compatibles) except rear cocking models, top cocking models, electronic models and VS models.

So, whats left? Side cocking only?

And, is this any good at all?