The Micro Traxion is Petzl's smaller, sleeker, sexier Mini Traxion. As with the Petzl Mini Traxion, the Micro Traxion is designed to be a progress capture pulley for hauling on big walls, rescue applications, and any other scenario where a progress capture pulley could be useful. The biggest changes from the Mini Traxion are that they boosted the efficiency of the pulley from 71 percent to 91 percent by introducing a sealed bearing, reduced the weight/bulk by 50 percent, and the rope clamp can be locked in the open position with the simple press of a button. Though we didn't test this, it is also touted to work on icy and muddy ropes, where the Mini Traxion can't.
Petzl's Micro Traxion has essentially all of the great features of the Mini Traxion, at half the size/weight. The jury is still out as to how the Micro will hold up over time as we haven't had enough time to put it to the test fully, but we are initially impressed with its overall form and function; pretty slick little device.
To see how the Mini Traxion compared against other solo top rope self-belay devices, see our article The Best Progress Capture Pulley or Ascender for Solo Self Belay Toproping.