The al-ko secure wheel lock attaches to the receiver, visible through the alloy spokes, which is permanently fixed to the wheel brake, to help protect against the theft of your caravan. with a wide variety of unique security features, the al-ko secure wheel lock is approved to sold secure diamond standard. Security features • I 33,000+ security combinations • Registered key management system • 9-pin anti-pick radial lock mechanism • Portable & easy to fit • Sold secure diamond approved - the highest standard • Insurance approved - discounts available for secure owners. • High load capability when subjected to attack • Highly visible anti-theft deterrent • Don't forget to register your lock. without registration replacement keys cannot be obtained. Caution! I the al-ko secure is alloy specific.