A cell permeable, competitive, and reversible inhibitor of cGKs that blocks activation of cGKI and cGKII by cGMP (Kis = 35 and 30 nM); less potently inhibits PKA (Ki = 11 µM) and cGMP-induced activation of cyclic nucleotide-gated channels (IC50 = 25 µM); resistant to hydrolysis by PDE11.