Steel City 1-Gang Metal Electrical Switch Box Extension

3 in. x 2 in. x 1 in. Device Box Extension. Fits inside single-Gang switch boxes. 7/8 in. depth adjustable.
Highlights
3-1/2 cu. in.
Fits snugly inside of all single-gang switch boxes
Maximum adjustable depth 7/8 in.
Furnished with 1-1/4 in. L screws for mounting