L1-Visa
The United States L1 visa is a non-immigrant visa which allows companies operating both in the US and abroad to transfer certain classes of employee from its foreign operations to the USA operations for up to seven years. The employee must have worked for a subsidiary, parent, affiliate or branch office of your US company outside of the US for at least one year out of the last three years.
Companies operating in the US, may apply to the relevant BCIS service center for an L1 visa to transfer someone to the US from their overseas operations. Employees in this category will, initially, be granted an L-1 visa for up to three years.
There are two types of employee who may be sponsored for USA L1 visas:

Managers/Executives (L-1)
The legal definition of management and executive roles for these purposes is quite strict, and a detailed description of the duties attached to the position will be required. In particular, the executive or manager should have supervisory responsibility for professional staff and/or for a key function, department or subdivision of the employer. Such personnel are issued an L1A visa, initially for a three year period extendible in 2 year increments to a maximum of 7 years.

Specialized Knowledge Staff (L1-B)
This category covers those with knowledge of the company's products/services, research, systems, proprietary techniques, management, or procedures. Staff in this category are issued an L1B visa, initially for three years extendible to a maximum of five years.
On completing the maximum allowable period in L-1 status, the employee must be employed outside the United States for a minimum of one year before a new application is made for L or H status

Dependents of L-1 Visa are eligible for L-2 Visa