The pair of boots you often see worn by workers climbing wooden utility poles for telephone, telegraph, or electric wires and cables are variously called tree climbers, tree spurs, tree hooks, and tree spikes. There are plenty of such climbers/spikes/spurs with different styles and designs and different brands. One of them is the Gecko II Tree Climber.
The Gecko II is a complete set that includes boots and spikes. The sturdy boots are high, rising up to right below the knee. This is needed to provide additional support for your shin. The leg shanks are made of aluminum alloy resulting to reduced weight. It stretches on the inside of the shin from the about the height of the boots down to its sole. Here it makes a 90° turn to support your instep. This support is designed in a way that it cups the foot arch, thus making it comfortable to step on.
The gaffs or spikes are also made of aluminum alloy that are easily sharpened. They are attached to the leg shanks at about the level of the ankles. These are kicked into the wood to provide a stable anchor as you climb.
A cuff made of fiberglass wraps the upper section of your shin for bracing. A wide cinch strap with Velcro secures the cuff to your leg and keeps it from moving. An inside padding, also attached with Velcro, makes the cuff comfortable to wear. This is removable for easy washing.
An adjustable belt at the ankle further secures the leg shank keeping it from sliding on or slipping from the instep. This can be adjusted from 41 to 48 cm, in increments of 2 cm.