San-X Sumikko Gurashi eraser.
Made of a special material that will glow in the dark.
The last picture show how it looks in the dark. The eraser on this listing is the ONE shown individually under normal lighting.
Size about 3/4 x 1 7/8 x 5/8 inch (2 x 4.5 x 1.5 cm)
San-X Japan 2022