Two important features make the Rock Exotica Screw-lock unique from all others. First, all aluminum parts are anodized. This is particularly important for the screw-sleeve and gate, since without this coating, it is more susceptible to corrosion. This protective surface also gives the sleeve a smoother spin.
Second, the gate was designed with an enlarged flange at the top. This prevents the screw-sleeve from moving past the end of the gate, whereas with other designs, the sleeve can wear past the last thread of the gate and slip off.
Auto-Lock Carabiner - RockO
Auto-Lock Carabiner - Pirate