Datasheet

The LEDs themselves do not connect to the Feather. Instead, a matrix
driver chip (HT16K33) does the multiplexing for you. The Feather
simply sends i2c commands to the chip to tell it what LEDs to light up
and it is handled for you. This takes a lot of the work and pin-
requirements off the Feather. Since it uses only I2C for control, it works
with any Feather and can share the I2C pins for other sensors or
displays.
This product kit comes with:
 A fully tested and assembled Adafruit 4-Digit 14-Segment
Alphanumeric Display FeatherWing
 Two sixteen pin headers
A bit of soldering is required to attach the matrix onto the
FeatherWing.
Note: Feather board and 14-segment display are not included.
 51mm x 23mm x 4.2mm / 2.0" x 0.9" x 0.165"
 Weight: 4.8g