MagnaCard, Inc Magnetic Vent Blocker, 5 x 12 Inches, 2 Vent Blockers (2 Packs), Colors May Vary (VB5/122) Value Pack! 2 - 2pks for a total of 4 white vent blockers Easy to use, place magnetic cover over vent. Instantly seals of unwanted airflow and directs air to the rooms you use most Cuts easily with sissors Blocks airflow by over 99% and helps reduce your fuel bills!