I have switched to 7" filter socks and no longer need these 4" ones. They were all bought in the middle of last year from Bulk Reef Supply. I used them when I was cycling my tank.
They are all 4"x14", felt material, 200 micron with plastic ring. All have them were always washed with baking soda, never bleached. All washed and ready to go.
Quantity 19 @ $4 each or all for $70
