Fully tested and working, original Apple AAUI to thin ethernet (10base2, coaxial) transceiver for use with any Macintosh with an AAUI ethernet port. Does not require any driver software other than the ethernet software in Mac OS and is self terminating so you do not need to use a BNC terminator if this is at the end of the chain.
Back in the day when ethernet came in three flavours; thick, thin and twisted pair, the transceiver was a way of building ethernet support into a Macintosh but allowing the type of ethernet to be decided by the transceiver you bought.