This item is used on multiple models.
On 40GLS and 25GLS:
Preset Knob Spring
On 50, 50S, 50SW: IMPORTANT NOTE: On some 50, 50S, 50SW reels, the 41-40 may be the spring being used, depending on the age of the drag setup.
Compare your spring to the one below to determine which one to order for your reel if replacing the spring.