For any thermistor with 3 mm diameter cartridge.

Assembly:

1. Print it
2. Cut out the thin section acting as a support (circled in one of the images)
3. Get thermistor wire through newly created crevice
4. Pull the wire further so that thermistor cartridge is pulled towads hole
5. Lightly press the cartridge into the hole
6. Thermistor should get about 5 millimeters in and then stay put.

Most likely suspects that fit:

a) ATC Semitec 104GT-2
b) ATC Semitec 104NT-4-R025H42G