Klein Tools MODbox Internal Rail Accessory secures all rail attachments inside MODBox Rolling Toolbox (Cat. No. 54802MB) and Medium Toolbox (Cat. No. 54803MB). Use handle side up or down depending on the clearance needed. Use with all rail attachments including the Tool Carrier (Cat. No. 54814MB), Parts Bin (Cat. No. 54815MB), Multi-Hook (Cat. No. 54816MB), Cup Holder (Cat. No. 54817MB), and Magnetic Strip (Cat. No. 54819MB).