http://www.amainhobbies.com/product_...ock-Bladders-4

Maybe these?? 13mm OFNA??

Will probably get theses
http://www.tsrproducts.com/index.php...3305-13mm.html

OI see, the slits are on the opposite side, like the OFNA ones
in the top link??...duh

more info on if the foams, and if they are a must use with either
of these.
THX all