A spanner is a tool used to provide grip and mechanical advantage in applying torque to turn objects such bolts and nuts to keep them from turning. BHT offers spanners in open-end, ring, and combination varieties. Open-ended spanners have U-shaped jaws with an opening the width of the nut or bolt head. They have two flat sides which grip opposite sides of a fastener in order to loosen or tighten it. Ring spanners are simple spanners with a profile that is enclosed in a ring. The heads are usually offset from the handle so it is easier to reach the fastener.Combination spanners are a simple spanner made up of a shaft and two spanner heads: one open-ended head and one ring head.