The NTE3078 (Common Anode) and NTE3079 (Common Cathode) are 0.56 inch (14.2mm) height single digit displays utilizing LED chips which are made from GaAsP on a GaAs substrate.
Full spec sheet:
https://www.nteinc.com/specs/3000to3099/pdf/nte3078.pdf
NTE3079 0.56” Single Digit Numeric Display Seven Segment, RHDP,
SKU: NTE3079
$3.53Price