An essential part of climbing kit PPE, carabiners are used daily by arborists and tree climbers everywhere. Triple-lock Carabiners (Sometimes referred to as Three-way & Autolock Carabiner) are the safety standard used in tree climbing. The DMM Durolock (4-way) Carabiners provide an extra level of Safety. Interesting fact: Carabiners are often spelt Karibiners. Even DMM (Caribiner) & ISC (Karibiner) can’t decide which is right!