Keeping a low profile can be a good thing. Constructed with a concrete core and an acrylic surface finish, the Ballast shower base by Kohler has a threshold that ranges from 1-5/8” to 3-7/32” tall. The short stature helps users to enter and exit easily, while creating a streamlined transition with surrounding floor finishes. The base requires less maintenance than a tiled shower floor and has less risk of leaking, according to the manufacturer. kohler.com