1 fully seeded Hydro V sponge which has sat in my disease free tank for 2+ years.  The sponge is worn, but contains lots and lots of bacteria involved in nitrogen cycling.  You can added this to an existing sponge filter to immediately cycle your tank.  If you have a power filter or a canister filter, just cut it up and cram it in.  Instant cycling!  If anyone bids on this, I'll put in a second sponge so no one has to pay more than $5.  All proceeds to MAS.