Arlington EMT350 Press Fit Insulation Bushings. 25 Pieces. Fits 3-1/2” EMT. The Arlington press fit or hammer on bushing is designed to fit snuggly on standard EMT sizes to provide protection for you cable from the edge of the cut EMT. These hammer on bushings are simple to install. On the smaller sizes, they tap on easily. As you move up to the larger sizes, you may want to use a hammer and a piece of lumber to protect the bushing from cracking. We like to use a rubber mallet. Please keep in mind the size of the bushing is a trade size so a 3-1/2” bushing will fit a 3-1/2” trade size EMT. The Arlington press fit insulations are available in sizes ranging from ½” up to 4” trade size.