maple classic™ 
@Jo oh here's a cheaper one, does basically the same thing and some more https://www.ebay.com/itm/VIDEO-CONVERTER-BOARD-ARCADE-GAME-GBS8220-RGB-CGA-EGA-YUV-to-VGA-ATARI-AMIGA/253397077597
@Jo also: some wiring guides from amiga to this specific board say you can tap the 5v out from the monitor port to power this board
DO NOT DO THAT
the 5v out on the amiga is 100mA, this board draws 1A
@Jo once you know what to look for it gets even cheaper https://www.ebay.com/itm/Video-Converter-CGA-EGA-YUV-RGB-TO-VGA-Arcade-Jamma-Game-Monitor-to-LCD-GBS-8220/222602687033