Legal analysis: 1. Without the signature or seal of the employer, this contract is invalid. What a contract needs is the signatures or seals of both parties. Signature and seal have the same legal effect, only one of them is required. But if it is a legal person, it is best to have a legal person seal.

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 stipulates that 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 principal.

Article 490 Where the parties conclude a contract in the form of a contract, the contract is formed when the parties sign, seal or fingerprint it. Before signing, sealing or fingerprinting, one party has fulfilled its main obligations, and the contract is established when the other party accepts it.

Note: The Civil Code came into effect on 20211.