Are you in need of extra storage space to avoid messy environment? Our 4-tier shelving unit is the perfect option for you. Its convenient folding design allows for easy expansion or folding as needed. Once unfolded, it provides 4 storage shelves to accommodate a variety of sundries. Additionally, all shelves can be assembled in 10 different positions, allowing for customizable storage based on your needs. If you require more vertical storage space, simply detach several shelves. Furthermore, our bookshelf is equipped with 4 universal wheels, making it easy to transport items from one place to another. Besides, 2 of wheels are lockable, ensuring the rack stays in place. Most importantly, this bookcase comes with anti-toppling device to maximize steadiness and security.