( 3 ) 16"x 13" Filter Media Bags for Aquarium filter,Pond filter, Bio ball, Bio ring, ¬ for ACTIVE CARBON, BECAUSE NET HOLES ARE  SIZE 4MM.

FEATURES:

1,Media bags allow the precise placement of filter media and ensure granular media doesn't travel through pumps and pipes.

2, Great for Bio-balls, bio-rings, phosphate removers, nitrate removers

3, Zipper design for Reusable

4, Size: 16" x 13", Net hole size: 4mm.

5, Made from 100% polyester, Heavy Duty.

INCLUDES:

(3) Black Media bags