Need handpiece for Unisonic model 9518x

SOURCE: We have an old Unisonic model 9325 corded phone

I have an old Unisonic 9725, and the programming method for that phone may work for yours.
1. take handset 'off hook'
2. press: store
3. enter phone no.
4. press store
5. press memory button 1, 2, or 3...or 0-9
6. put handset back 'on-hook'

to use: take handset off hook, and press the memory number that applies.