What is this (circled) part on a spinning reel? What is it for? 40

Fishing Reel Stock Illustrations – 14,756 Fishing Reel Stock Illustrations, Vectors & Clipart - Dreamstime

Stealth 62Ti - Alvey Australia

Ori0n_SSB (u/MuffinHat) - Reddit

Fishing Reel Stock Illustrations – 14,756 Fishing Reel Stock Illustrations, Vectors & Clipart - Dreamstime

LS Baitfeeder Spinning Reel OKUMA Fishing Rods and Reels - OKUMA FISHING TACKLE CO., LTD.

Ori0n_SSB (u/MuffinHat) - Reddit

Cressi Fishing Reel, Black, 130 ft 40 m : : Sports & Outdoors

Ori0n_SSB (u/MuffinHat) - Reddit

Coonor Fishing Reel With Double Line Cup 12+1BB Gear Ratio 4.6:1

Tune-Up Tuesday: Anatomy of a Spinning Reel

DannyLee1992 (u/DannyLee1992) - Reddit