The Logitech G502 HERO has an updated sensor and a more flexible cord. Logitech was careful not to change much from what made the G502 such a classic.
Logitech G502 Lightspeed gaming mouse review: The juggernaut
Logitech G502 LightSpeed Review: The Ultimate Gaming Mouse That Will Give The Extra Edge
Logitech's G502 Lightspeed is a wireless version of the fan-favorite gaming mouse - The Verge
Logitech G502 X Lightspeed review
Logitech G502 Lightspeed Review
Logitech G502 Proteus Spectrum Review
Logitech G502 X Review: 'Return of the Many-buttoned Ergo King' - GameRevolution
Logitech G502 Hero review: A slight improvement on an old standard
Selling Wireless Gaming Gear Brand - Based on independent sales data (FEB '19 - FEB'20) of Wireless Gaming Keyboard, Mice, and PC Headset in units
Logitech G502 Lightspeed Wireless Gaming Mouse with Hero 25K Sensor, PowerPlay Compatible, Tunable Weights and Lightsync RGB - Black
Logitech G502 Lightspeed Wireless Gaming Mouse Review - IGN
Logitech G502 X Lightspeed review: The perfect mouse for MMO players
Logitech G502 X Lightspeed review
Logitech G502 Lightspeed Mouse Review: Who Needs Wires?
Logitech G502 Lightspeed Wireless Gaming Mouse Review