You are bidding on the Single comic published by DC, Challengers of the Unknown #57 (Aug-Sept 1967) in G/VG condition by Overstreet standards (see below)
Shows substantial wear. Must be readable. Discoloration, fading and soiling likely. Small pieces may be missing, but the readability is preserved. Store stamp, name stamp, arrival dat, intial's permitted. Staples mey be degraded, absent, or replaced. Cover may be detached. Coupon may be cut from back cover or from an interior page as long as story readability is preserved. Pages may be brown but not brittle. Tape and other forms of repair are common.
35-54 (Very Good)
Shows significant wear. Book-length creases or dimples. Spine roll. Some discoloration, fading and soiling. Small piece cam be out of cover from an otherwise finer copy. Store stamp, name stamp, arrival date, or initials. Staples me be discolored with rust migration. Centerfold may be detached. Minor printing and/or bindery defects. Pages may be brown. Minor tape repair on an otherwise better copy.
Overstreet Guide Values for this comic
Near Mint $45.00
Very Fine $27.00
Very Good $8.00