Apple USB Ethernet Adapter Price: £29.99 (as of 08/08/2022 12:46 PST- Details)

Small and light, it connects to the USB 2.0 port of your MacBook Air and provides an RJ-45 connector that supports 10/100BASE-T performance.
4.6 inch USB cable
Requires Mac OS X v.10.4.8 or later and an available USB 2.0 port