The phrase "new calipers" refers to a type of tool used in mechanics to measure distances or thickness. It means that a fresh or unused set of these tools is being referred to. Full definition
It has had a complete brake service with new calipers on all four wheels, as well as a new power brake booster and master cylinder. (barrett-jackson.com)
The suspension kit lowers the car 0.4 inch (10 mm) and includes stiffer springs and a thicker front stabilizer bar to enhance cornering capability, while the brake kit features larger - diameter front rotors and new calipers for greater braking capability. (gm.com)
It features larger, 11.8 - inch - diameter (300 mm) front Duralife vented and slotted rotors and new calipers versus the stock 10.9 - inch (276 mm) rotors. (gm.com)