At a mere 115 grams you can tell that some very precise German engineering went into the Rolhoff XC/SS Chain Tensioner. As if you couldn't tell just by looking at it! These are all around solid and that''s probably why people are recommending them for trials riding on top of all around trail.
The Rolhoff Chain Tensioner mounts to a normal derailleur hanger and features a stout spring and short body to keep your chain where it''s supposed to be, on the rings. Rolhoff even says these can work with many full suspension set-ups that go single speed. That''s because these have a chain tensioning capacity of 10 links which is huge!