Box Extender - Single Gang Use a box extender when you want to bring the electrical device flush to the wall surface. The single gang extender will work for a single device only. Ask for our Installation Tips for more information on how to install and use. Price: 1-3 $4.00 Each 4 -7 $3.50 Each 8 -11 $3.25 Each 12 + $3.00 Each Product Id: X1 Unit of Measure: Each Quantity: