Mark E Industries. Remodelers doing more universal-design work will appreciate the easy-to-install Handi-Kirb for shower projects. The system creates a roll-in, wheelchair-accessible shower when recessing the compartment floor is either impossible or not practical. Suitable for any size shower, Handi-Kirb measures 30 inches long and features dove-tail connectors to accommodate any length shower opening. The unit is adjustable to as low as 5/8 inch in height, not including the height of the tile, and can be used on concrete or wood subfloors. 866.771.9470.