Un-A-Lok Liners are similar to HL head liners, except that they incorporate a sturdy locking tab that eliminates the need for a Lockscrew. UL Liners are permanent bushings used to hold SF renewable drill bushings. Although slightly more expensive than a head liner plus a Lockscrew, installation time is dramatically reduced.
Un-A-Lok Liners are functionally similar to Head Liner Bushings, except that they incorporate a sturdy locking tab that eliminates the need for a Lockscrew, reducing installation time dramatically.

Standard Liner ID Tolerance:
Standard OD Tolerance:
Unground OD Tolerance:
| Material | Heat Treat | Finish | DFARS | RoHS | |
| 1144 Stressproof Steel | Heat treated to achieve Rc 62-64 ID hardness | - | ✔ | ✔ |
| ID (Inch) | OD (Inch) | Length (Inch) | E (Inch) | F Diameter (Inch) | G (Inch) |
| 3/4" | 1" | 1" | 21/32" | 1-1/16" | 1/8" |