The Hammer Extension from Grovtec is designed to give the shooter more surface area while engaging the hammer. This extension fits the Marlin 36 (1936-1947) and 336 (1948-1956).
Specifications:

Type	Hammer Extension
Model	Hammer Extension
Dimensions
Size	Marlin 36 & 336
Material	Steel
Action
Trigger
Safety
Thread Pattern
Finish	Black
Bolt Type
Hand	Ambidextrous
Hammer Type
Max Capacity