This is a high-performance replacement laptop charger for the Chem USA ChemBook 3812. ChemBook 3812A, guaranteed to meet or exceed the OEM specifications of your original. The laptop charger is 9.5 x 6 x 2.5 inches. Manufactured by Empire Scientific, model number LTAC-090. We offer a 1 Year Warranty with purchase. See this product elsewhere at a lower price? Call or email us; we have a Price Match Guarantee.