A carabiner or kayak opener is a specific kind of lock, a simple metal loop having a single spring-loaded door-closeable gate that is used to fasten materials, most notably on high-security systems. Carabiners can be locked as normal, but when closed, the two blades retract into the body of the device, forming a U-shaped wedge between the blade and the gate. This enables secure tightening of the metal loop and allows easy opening of the gate.
There are two types of carabiner: screw-lock and twist-lock. Screw-lock carabiners are more prone to damage and misuse due to their frequent and expensive incorporation of non-standard components and materials. The parts may include screws and pins that are not easily accessible for the average user, making them less prone to misuse by inexperienced users who may misuse small devices such as carabiners for purposes other than securing cargo. The advantage is that the parts are less prone to damage in the event of a fall, a broken screw or pin or other possible mechanism causing the carabiner to detach from the gate during use. They are also less prone to damage if they are poorly manufactured and not designed for long-term or repeated use.
Twist-lock carabiners, on the other hand, are built with stronger materials and more durable designs. This makes them less vulnerable to wear and tear, making them ideal for harsh environments. While being more expensive, they provide a higher level of locking efficiency as well as increased durability against external threats such as sunlight and weather. They have a higher degree of locking strength, making them less susceptible to damage in the event of a fall. In terms of security and strength ratings, both types of carabiners are virtually identical.