SUPERIOR QUALITY: Sliding bifold barn door hardware is made of high-quality carbon steel with frosted black surface. All nylon wheels have been tested beyond 100,000 rolls, smoothly and quietly. PRODUCT DIMENSIONS: Track length: 36. The track length should be door opening size + 4″ (100mm), at least 5-3/8″ clearance needed from top of door to ceiling, fit max door leaf width 16″, fit door thickness: 1″1-3/4. Door weight capacity: 180 LB. PACKAGE INCLUDED: 1x 3 FT Rail, 3x Rail Spacers, 2x Rollers, 2x Roller Brackets, 1 Fixed Connectors, 1x Floor Guides, 3x Hex Key, 3x Hinges. PLEASE BE ADVISED THAT THERE IS NO DOORS INCLUDE. EASY TO INSTALL: We provide step-by-step graphic and text instruction. All measurements in inch. It is very easy for you to take a reference during the installation. Our engineering team is composed of experts.