List of items required for one pair of gerbils:

Here is the minimum required:

• 20 Long Tank (40 gallon is always better)
• Screen Top
• Exercise Wheel (8" is minimum, my reco is 10", both these sizes fit in the 20 gallon)
• Aspen or Cozy Comfort Bedding
• Wood Hut (for security and sleeping)
• Wood Chew toys
• Sand for bathing 
• Jar or glass bowl for sand
• Water bottle with holder
• Food (Kaytee Pro Health or Higgins Sunburst Gourmet Blend)

Look at my favorite products article to see the brand of items I recommend.