A winch is a static piece of equipment placed on the deck of your boat that allows you to multiply the traction exerted on the ropes (sheets, halyards, spinnaker arm) used to control the sails.
Pro winches are more powerful winches than those already equipped on your boat, and will allow you to maneuver even more efficiently!
Indeed, manoeuvring takes time! You have to get on the deck, take out the sails, hoist them, pull, slacken...
With pro winches, this maneuvering time is reduced and your boat will maneuver much faster during tack turns and gybes, but also when changing sails.