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| Challengers of the Unknown #21 | ||
| DC Comics, 8-9/61 | ||
| France Herron story | 2nd appearance of Cosmo. | |
| Bob Brown cover and art | ||
| Books | CGC Label | CGC Total | Avg. Grade | 10 | 9.9 | 9.8 | 9.6 | 9.4 | 9.2 | 9.0 | 8.5 | 8.0 | 7.5 | 7.0 | 6.5 | 6.0 | 5.5 | 5.0 | 4.5 | 4.0 | 3.5 | 3.0 | 2.5 | 2.0 | 1.8 | 1.5 | 1.0 | 0.5 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 BOOK | Universal | 25 | 6.62 | 0 0.00% | 0 0.00% | 0 0.0% | 0 0.0% | 0 0.0% | 3 12.0% | 1 16.0% | 1 20.0% | 1 24.0% | 5 44.0% | 4 60% | 1 64% | 1 68% | 2 76% | 3 88% | 0 88% | 0 88% | 1 92% | 1 96% | 0 96% | 1 100% | 0 100% | 0 100% | 0 100% | 0 100% |
| 1 BOOK | Restored | 1 | 8.00 | 0 0.00% | 0 0.00% | 0 0.0% | 0 0.0% | 0 0.0% | 0 0.0% | 0 0.0% | 0 0.0% | 1 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% |
| 1 BOOK | Qualified | 1 | 8.00 | 0 0.00% | 0 0.00% | 0 0.0% | 0 0.0% | 0 0.0% | 0 0.0% | 0 0.0% | 0 0.0% | 1 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% | 0 100% |
| Challengers of the Unknown #21 (1961, DC Comics) CGC Universal Grade Distribution | ||||||||||||||||||||||||
| 0% 0 10 | 0% 0 9.9 | 0% 0 9.8 | 0% 0 9.6 | 0% 0 9.4 | 12% 3 9.2 | 4% 1 9.0 | 4% 1 8.5 | 4% 1 8.0 | 20% 5 7.5 | 16% 4 7.0 | 4% 1 6.5 | 4% 1 6.0 | 8% 2 5.5 | 12% 3 5.0 | 0% 0 4.5 | 0% 0 4.0 | 4% 1 3.5 | 4% 1 3.0 | 0% 0 2.5 | 4% 1 2.0 | 0% 0 1.8 | 0% 0 1.5 | 0% 0 1.0 | 0% 0 0.5 |
| cgcdata.com, last updated September 16, 2025 | ||||||||||||||||||||||||