Details
Trek Rail uses 40 mm centred pin and 57.5 mm stroke shock (150 mm travel)
Trek Remedy uses 50 mm offset pin and 57.5 mm stroke shock (150 mm travel)
Trek Slash 2018-2020 uses 50 mm offset pin and 57.5 mm stroke shock (150 mm travel)
Trek Slash 2021+ uses 40 mm centred pin and 62.5 mm stroke shock. (160 mm travel)
Increasing shock stroke (and bike travel) requires careful checks of clearance at full compression.
Check piggy back clearance carefully. Especially Trek Rail.
Different frame sizes will have different clearance even in the same model.