An 'ΙΣ ΧΣ ΝΙΚΑ' (Ἰησοῦς Χριστὸς νικᾷ) christogram translates as "Jesus Christ Conquers". It is located in the four corners of the cross, which is a depiction of the 'ΙΣ ΧΣ ΝΙΚΑ' arrangement according to medieval Greek tradition.
Orthodox symbols
Enamel stickers with orthodox symbols. Can be applied to any surface. For best results, preheat the sticker with a hair dryer: direct hot air at the sticker and heat it for at least a minute to soften the surface.
