Those are Code 3 Optix. They make or made those to insert into headlight / taillight / corner light assemblies. I'm not sure if they are still available.
Had blue/blue in the front headlamps of a 2001 Impala 9C1. They were ok, nothing to write to home about - I think they were hooked up to a Code 3 700 or 710 flasher in I remember correctly.