All cable safety sleeves have the same purpose and function the same way: they attach to your chest D-ring and lock onto the cable attached to the safe climb system in the event of a fall. While they all serve the same purpose, not all cable safety sleeves are made equal. Some things to consider when looking at a new cable safety sleeve are
Ease:
How easy it is to install on the rope (some cable grabs require two hands, while others can be installed with one.
Safety:
Does it have added safety features (like the inability to install the device on the rope if it is upside down).
Handling:
How does it handle cable guides (does the cable safety sleeve glide over cable guides without requiring any effort from you)
Compatibility:
What size rope is it compatible with.