The plastic is flimsy but once everything is in place this shouldn't be a problem. They worked for outlets that were set to 1/2" drywall but needed a 5/8" that fitted nicely into the existing outlet and also for outlets that were set to 2X4 but after the drywall was in place. and a 1/2" decorative rosette was placed above it. They filled in the space, widened the exhaust box and helped stabilize the exhaust when a metal cap was fitted with it, alleviating concerns about gaps that were already there. I already have them used to fix other outlets and junction boxes that I found with this problem.