TTL logic, plastic case and part of the 74 series of devices which were released in 1966 and became the industry de-facto standard.
Look inside any electronic equipment from the 1970's ~ 1980's and it is very likely you will find some 74xx devices.
This device is from the 74AC series, one of the earliest CMOS versions with about the same gate speed but much lower power consumption compared to standard TTL.
FAIRCHILD SEMICONDUCTORS
Made in Singapore
Type: 74AC258
Part #: 74AC258PC
Function: Quad 2-Input Data Selector/Multiplexer with 3-State Outputs
16 pin DIL plastic
NEW Old Stock
Always stored & these will be supplied in a suitable ESD tube
NEW Old Stock
