I have tested D2504070A.JCV (approx 600Mb), D3084040A.JCV (approx 300Mb) and D3589020A.JCV (approx 120Mb) on nuvi 1200 and nuvi 1450. I did not see any difference between first two ones, but the third - D3589020A.JCV (approx 120Mb) - did not show up. My recommend for the 1200 series and 1450 is D3084040A.JCV.