1 unit,  the pictures is for display only

Pre Filter Bag is design for Aquarium Use.

 Feature

• Suitable for Pre Filter sand / rocks in the sump
• 200 high micron can filter copper in the water (See Video / Picture)
• Prevent any sand /rocks filtering, and protect for your skimmer avoid broken by rocks
• Easy to clean and reuse to wash

Specification

• 200microns 4" x 14" Or 7" x 14" 
• Better can combine with our pre filter mount to use

video

http://www.youtube.com/watch?v=gR7OTSIqySo