Guitar chords in the key of G:
Chord G7-5 (5th fret) notes: G, Db, F and B. You must leave out the 6th and 5th strings.
G dominant 7th flat 5th guitar chord's alternative names: G7b5, Gdom7b5.
1(G), 3(B), b5(C#/Db), b7(F).