. . . . . "Such regulations may include, but are not limited to: (1) regulations defining and governing outside salesmen; (2) learners and apprentices, and their number and pay; (3) special pay for special or extra work; (4) charges to employees for allowances for board, lodging, apparel or other facilities or services customarily furnished by employers to employees; (5) allowances for gratuities; (6) allowa" . .