The ice castle works on the principle of melting ice. It is perfect for self bondage. Simply fill it with water, insert the second rod and the excess water will come out. Then put it in the ice compartment. There is a hole on the outer tube that prevents the lock from being blown up by freezing water. Capacity approx. 100ml. The opening time depends on the ambient temperature, this lock opens after about 3.5 hours at a temperature of 20°C. The two eyelets (3cm) at the ends are for attaching ropes. The total length is 170mm. Cylinder length is approx. 75mm. The diameter is 50mm. Total weight approx. 480 grams. Material stainless steel.