Nabco/Nabtesco was one of the two OEMs Nissan used to produce the brake and clutch operating cylinders for the S13/14/15 platform, Tokico was the other one. Tokico no longer produces these for Nissan, all of the genuine new Nissan units left are all made by Nabco. 

Nabco clutch slave cylinder - These fit to all RWD S13/14/15 using the CA/KA/SR transmission.
 
This replaces genuine Nissan part number 30620-69F01