They fit down inside the ram tubes and at this point are only available for Enderle's current big block and small block injectors. Every brand's ram tubes vary wildy on ID...they'd have to be custom made to fit others. I don't have any pics available right now. Thus far, they are only available with our EFI system (
http://fuelinjectionent.com/webstore/product_info.php?products_id=412 ). If you have one of their newer setups and you think they'd fit, or are interested in having a custom set made for something else, give a call. I don't remember the filter diameters and I'm not in the shop today. A custom set of eight would run $300ish.
They are only for street use. If a guy were running wide open in a racing application, they would certainly cause a loss of power at the top end. They work really well running stacks on the street in an EFI situation however.
Thanks!
Spud