【ADVANTAGE OF OUR FILTERS】 Insert our air filter into the air vent registers to purify the air coming from your AC units and heaters 【PACKAGE CONTENTS】 24 Pack of 4" x 12" Air Vent Filters for Home Floor 4 x 12 Inch 【DIMENSION】 4x12 inches. Easily trimmed with scissors to the size you need. This filter is thin, and can eliminate odors while increasing air circulation 【COMPATIBLE WITH】 Floor, wall, ceiling, and baseboard register & grilles in bedrooms, offices, schools, hospitals, or any living space 【REPLACEMENT TIME】 For best performance, it is recommended to replace the air vent filters every 3-6 months Floor Vent Filters, Air Vent Filters for Home 4" x 12" Breathe green, be thankful for life What is in the box: 4" x 12" Premium Register Air Filters Thin, total 24 packs.Design: ①✂️ Easily trimmed with scissors to the size you need. ② Thickened: Our newest register filter has been thickened and its density has been increased by approximately two times Tips: Replacement Time: for best performance, it is recommended to replace the carbon filter every 3-6 months.