Question about Thule SnowPack M

The Thule SnowPack M is securely mounted on a Thule WingBar Evo as it is specially designed for these roof racks. The key for the Thule WingBar Evo is for the security of the roof rack itself, while the SnowPack M has its own security features to secure the skis or snowboards. The SnowPack M cannot be easily removed as it is firmly attached to the roof rack. The safety of the SnowPack M is guaranteed by its own locking functions, which secure the skis or snowboards to the carrier.