Focus Whistler 3.6 Bicycle Grey. When you face risky situations, you need a partner you can trust. That's why the Whistler has been fitted with disc brakes, to ensure consistent braking performance and optimal braking behavior in all weather conditions. Wiring runs through the frame's downtube for better cable protection, increased durability, and a clean aesthetic. So that you can fully adapt your bike to your needs, you have the option of mounting a rack, mudguards, light and kickstand.