The Professional Hand Ascender from ISC is designed for industrial use. The cam does not have spiked teeth that pick at the rope sheath( see the data sheet for more detail). This also helps it release when pushed up against a knot or pulley.
The very nice ergonomic design makes this comfortable to use. No rope running over the back of your hand when pushing it along the rope.
Machined from a single piece of aluminium, these are hard-working and hard-wearing. There are cheaper hand ascenders available, but this should last a lifetime!
You can download the data sheet here.
Please select left or right hand.