From Grazr:

The Zone Pro is the ultimate answer to a singlespeed tensioner. Created to prioritise adjustability and maximum chain retention, the ZonePro is adaptable to almost every bike and setup. Built from a combination of 6061 and 7075 Aluminium, it not only features an adjustable clutch with 26 clicks of adjustment, but is also completely rebuildable and designed to stand the test of time.

Specifications

• Compatible with standard-fit derailleur hangers
• Main body and clamp machined with 6061 aluminium, jockey wheel cage machined with 7075 aluminium.
• Durable jockey wheels machined from 7075 aluminium, with replaceable 689-2RS bearings.
• Hardware made from 304 stainless steel
• The shaft rotates on an XFM IGUS bushing for prolonged durability and wear resistance compared to standard G-spec bushings.
• Carbon fibre clutch plates reduce wear and increase heat resistance, leading to more consistent chain retention.
• Adjustable clutch tension, with 26 definable clicks of adjustment.
• Adjustable main body position allows for 19mm of chainline adjustment, to keep things running straight, reducing chain wear and increasing chain retention.
• Compatible with 12t - 18t cogs
• Integrated cage latch for easy rear wheel removal