Holy hell...What did I find?!

This was a COMPLETE surprise. I'm walking through an antique store and flashing my light around (365 so I find all that tasty glaze and custard) and what should appear but these two "egg" cups. Tag said Czech Tango (?) Glass, so they had no idea what they had.

But honestly...neither do I. 😅 I know they glow and they just blasted my radium dial clock out of the water in sievert count. But are these really "Czech" or "Tango"? Any info would be great! Thanks!

P.S. I paid $8.80 for both. YES, YOU READ THAT RIGHT: EIGHT DOLLARS AND EIGHTY CENTS. 🤯🤌🥳