There are a few APEM tactile switch parts with an added “L” suffix that isn’t listed on the datasheet.
Per the manufacturer -
The L indicated Long life. The L options are built with a stainless steel dome that will reach up to 1 million cycles where the standard part is made from a Phosphor bronze that will get you about 100K cycles or so depending on the model.
|Apem Part #||Mechanical Life Cycles||Packaging|
|MJTP1138TR||100,000||Tape and Reel|
|MJTP1138LTR||1,000,000||Tape and Reel|
|DK Part #||Mfr Part #|