Legal analysis: the contract is invalid without the signature or seal of the employer. 2. If the unit only signs but doesn't seal or only seals and doesn't sign, as long as the legal representative of this unit performs his duties, that is, signs or seals on behalf of the unit, instead of signing a contract for his own affairs in his own name, then the contract is valid for the unit.

Legal basis: Article 165 of the Civil Code of People's Republic of China (PRC) * * * If the power of attorney is in written form, the power of attorney shall specify the agent's name, agency matters, authority and time limit, and shall be signed or sealed by the client.