| 2026-06-02 | Letter-shaped groove for a fastener |
| 2025-07-13 | Letter-shaped opening |
| 2024-07-01 | Letter-shaped opening for a bolt |
| 2024-02-11 | Letter-shaped groove used in framing |
| 2023-08-08 | Groove for a letter-shaped bolt |
| 2023-01-17 | Letter-shaped opening in hardware |
| 2020-07-15 | Letter-shaped opening for a bolt |
| 2020-04-25 | Letter-shaped opening |
| 2019-02-15 | Opening for 31-Down |
| 2017-09-04 | Letter-shaped track in metalworking |
| 2014-06-22 | Letter-shaped opening in a machine shop |
| 2012-03-18 | Letter-shaped opening in some pistons |
| 2012-02-10 | A weather strip may fit into it |
| 2009-02-04 | Groove for a letter-shaped bolt |
| 2008-01-01 | Letter-shaped opening for a bolt |
| 2004-11-19 | Letter-shaped opening |
| 2002-02-02 | Letter-shaped opening |