LEGO Transparent Red Electric Light Brick 2 x 3 x 1.3 Red (38564 / 54869) | Brick Owl - LEGO Marketplace
LEGO Light Brick Internals and Color LED Replacement - YouTube
BrickLink - Part 54930c01 : LEGO Electric, Light Brick 2 x 3 x 1 1/3 with Trans-Red Top and Red LED Light [Electric, Light & Sound] - BrickLink Reference Catalog