Pair of vibration alert keychains

I am looking for an experienced freelancer to help me design and produce a pair of vibration alert keychains for a special hard of hearing project. The keychains must be able to generate medium-intensity vibrations, the goal is for both devices to be able to send and receive the signal so either keychain holder can be alerted, and should be powered by button batteries or similar. The preferred material for these keychains is plastic, as this will ensure they are light and easy to carry around. The selected freelancer must have extensive experience in designing and producing these keychains and must guarantee that the quality of their work is up to the highest standards. If you're interested in this project, please let me know and I would be happy to consider your offer!