goof proof standard liner shower floor kit mark e industries standard shower kits permit easy construction of shower floors with the proper minimum water drainage slope of 1/4 per 12" run. these time saving kits permits construction of standard 36" x 60" shower areas with a centered drain. custom shower kits and additional components are available to accommodate areas up to 144" x 144" with centered drain. mark e industries has created 8 shower installation products to simplify the art of shower and tile installation by focusing on some of the industry's more difficult and time consuming tasks. tools that will save the installer the valuable time required to complete such tasks, without the problems that can occur with traditional methods.