Received some questions on using Mar Bars. I love the things even though many consider them dated.
This video show my favorite way to use them/back them up with a basal anchor system.
My favorite tether is an ART Snake Tail, but I left it in another truck this morning so it is not in the video
The key to proper Mar Bar ascent is a short tether and letting your legs do the work not trying a series of pull ups into the tree!
I keep my arms pretty much bent at the elbow 90º the whole ascent. I bring my legs up till my thighs are parallel to the ground, just like I am sitting in an imaginary chair. Short even steps.