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Model: Chess Challenger 10
Manufacturer: Fidelity International
Year: 1979
Est. ELO rating: 1200
Levels of play:10
Processor: Z80A @4 MHz
Programmer: Ron C Nelson
Type: Keypad / Calculator with magnetic pieces

Fidelity Chess Challenger 10. Model CCX.  The manual indicates that level 7 is for postal chess (by mail) and the average response time is 24 hours! It seems there were three versions of this computer, being the CC 10C the rarest. From what I have heard they had minor differences.
Here's a complete list of the levels of play with the average response time:

CL1 - Beginner -          5 Seconds
CL2 - Intermediate -     15 Seconds
CL3 - Experienced  -     35 Seconds
CL4 - Advanced -       1:20 minutes
CL5 - Superior -       2:20 minutes
CL6 - Mate in 2 -        60 minutes
CL7 - Postal chess -     24 hours
CL8 - Expert -           11 minutes
CL9 - Excellent -         6 minutes
CL10 - Tournament -       3 minutes