lock ons. i've actually killed deer out of my lock on stands. anytime i take a climber out, i can never find a good straight tree, i make a ton of noise, i sweat like a pig when i'm in the process of climbing, and i haven't found one yet that's as comfortable as the aluminum lock on i bought at a yard sale for $20. oh yeah, and you can actually secure them to the tree, i've slid down several times (once from around 15 feet) in the process of climbing.