Please check the dimensions of your fishing reel knobs at shafts. Shimano A and Shimano B, Daiwa S and Daiwa L. For spinning reels with automatic bail return system, knobs less than 20g are recommended for up to 4000 models, or unintended bail return might happen.
Shimano rubber knob, made of very durable hard rubber not melting in time. To replace Cepton knobs, which melt in 3-5 years. These knobs were used on Japan version Calcutta reels only. Fitting: Shimano A color dark brown, with gold cap.