18" X 18" Plastic Access Panel Removeable/Reversable Door With Frame For Concealed Wall / Ceiling Application - [Outer Dimensions: 20" Width X 20" Height] Black + Product Details Size – Suitable for all AC 8in diameter 12125SDCLNGBX

+ Product Details Size – 26"w X 14"h is the size for the duct opening measurement only

Incorporated with Integral Butterfly Damper for full Airflow Control

+ Product Details Size – 8"w X 16"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 18" x 26" OR 26" x 18" duct opening (measured at the opening)

18" X 18" Plastic Access Panel Removeable Reversable Door With Frame For Concealed Wall Ceiling Application [Outer Dimensions: 20" Width X 20" Height] Black + Product Details Size – Suitable for all AC 8in diameter 12125SDCLNGBX + Product Details Size – 26"w X 14"h is the size for the duct opening measurement only Incorporated with Integral Butterfly Damper for full Airflow Control